Math Is Fun Forum
You are not logged in.
- Topics: Active | Unanswered
#1 2011-05-26 03:21:26
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Point Slope Form of an Equation
11-In January, Sam's electric bill was 115.00 dollars. In May, it was 83.00 dollars. Using the number of the month, for example January would be 1, February would be 2, etc, write two ordered pairs to represent the two electric bills.
11- (1,115) , (2,83)
12-Find the slope-intercept form of the equation that goes through these two points.
12- 83-115/2-1 =-32/1= -32
y=-32x+b
83=-32(2)+b
83=-64+b
147=b
y= -32x+147
13. Find the point-slope form of the equation that goes through these two points.
13- y-115=-32(x-1)
y-115=-32x--32
y=-32x- -147
y=-32x+147
14.If this trend continues, what will Sam's bill be in July?
am really confused on the rest help please 
15.At Generic High School, in the year 2001, there were 20 students per every computer. In 2008, there were 4.5 students per computer. Write two ordered pairs to represent the ratio of student to computer.
16. Find the slope-intercept form of the equation that goes through these two points.
17. Find the point-slope form of the equation that goes through these two points.
18.During which year was there 10 computers per student?
Last edited by zee-f (2011-05-26 03:25:46)
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#2 2011-05-26 03:27:34
- anonimnystefy
- Real Member
- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,049
Re: Point Slope Form of an Equation
hi zee-f,
14. find y for x=7 in the function you got.
15,16,17,18 corespond to 11,12,13,14.
Last edited by anonimnystefy (2011-05-26 03:29:25)
Here lies the reader who will never open this book. He is forever dead.
Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.
Offline
#3 2011-05-26 03:44:07
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
? am still confused
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#4 2011-05-26 04:14:08
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Point Slope Form of an Equation
Hi zee-f;
Welcome to the forum.
11 is incorrect, please start there.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#5 2011-05-26 08:32:01
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
so should it be (115,1) , (83,2)?
please help because am trying to finish my algebra online lessons fast 
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#6 2011-05-26 08:46:14
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Point Slope Form of an Equation
I am helping, but it will not be fast.
The coordinates are (x,y). No matter which one you choose to be x , you must be consistent.
(1,115) represents the first month and 115 dollars.
1st month is January, what is the number for May?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#7 2011-05-26 08:49:32
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
so it would be (1,115) and (5, 83). right?
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#8 2011-05-26 08:51:27
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Point Slope Form of an Equation
Correct!
Now take a look at 12. Does that equation really pass through both points?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#9 2011-05-26 09:05:08
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
y=mx+b
y=8x+b
83=8(5)+b
83=40+b
83-40=b
43=b
y=8X+43
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#10 2011-05-26 09:12:08
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
y-115=(-8)(x-1)
y-115=-8x-8
y=-8X- -107
y=-8x+107
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#11 2011-05-26 09:17:19
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Point Slope Form of an Equation
How did you get that slope?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#12 2011-05-26 09:19:22
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
y-y1\x-x1
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#13 2011-05-26 09:23:26
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Point Slope Form of an Equation
Hi;
Look at this line:
y-115=(-8)(x-1)
What is (-8)*(-1) ?
I guess he/she is not coming back. I think I will have some dinner.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#14 2011-05-26 20:11:40
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
is 8
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#15 2011-05-26 20:21:59
- Bob
- Administrator
- Registered: 2010-06-20
- Posts: 10,583
Re: Point Slope Form of an Equation
correct 
Bob
Last edited by Bob (2011-05-26 20:22:14)
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob
Offline
#16 2011-05-27 03:51:25
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
ok so what about 14 its confusing
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#17 2011-05-27 03:55:27
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Point Slope Form of an Equation
In order to do 14 you need to have an equation that passes throught the two points you do know. A correct one! Do you have an equation now?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#18 2011-05-27 05:18:41
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
nop can u give me an equation
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#19 2011-05-27 05:37:23
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Point Slope Form of an Equation
So then actually we are working on 13:
What did you get for slope of those two points?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#20 2011-05-27 06:00:23
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
y=-32x+147
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#21 2011-05-27 06:01:28
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
y=mx+b
y=8x+b
83=8(5)+b
83=40+b
83-40=b
43=b
y=8X+43
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#22 2011-05-27 06:05:15
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Point Slope Form of an Equation
The equation is not correct, first of all you do not have the right slope.
Do you know how to get the slope?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#23 2011-05-27 06:22:05
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
y-83=8(x-5)
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#24 2011-05-27 06:23:29
- zee-f
- Member
- Registered: 2011-05-12
- Posts: 1,220
Re: Point Slope Form of an Equation
isint the slope 8 ? because 32/4=8
One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3
Offline
#25 2011-05-27 06:26:14
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Point Slope Form of an Equation
You are not being consistent in the order of your subtractions.
What is?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline