Point Slope Form of an Equation

bobbym · 2011-05-29 01:26:13

Subtracting 20 from both sides does not cancel the -20.

-20 - 20 = - 40. Not 0

zee-f · 2011-05-29 01:27:46

am spouse to cancel the 20 next to the y right ? so its not a negative 20

bobbym · 2011-05-29 01:30:56

You have to add 20 to do that.

y-k=m(x-h)
y-20=-31\14X- -62031\14
-20 -20
Y=-31/14x- -62311/14 This is incorrect

Correct is y - 40 = ( - 31 / 14 ) x + (62031 / 14) - 20

You have not accomplished anything. Adding 20 to both sides cancels the 20.

Bob · 2011-05-29 01:41:40

hi zee-f and bobbym

Before you jump ahead, don't you think you want to check this answer.
zee-f wrote:
y-20=-31/14x-62031\14
Have you tried plugging x = 2001 into that?

Yes, this is wrong but the line above was ok, which was the answer to the question. Just a minus minus error here zee-f.
Take care with that sort of thing.

In post #40

y= -31/14x+62311/14

is a correct equation although I would prefer it like this

y = -31x/14 + 62311/14

Now in post #44 you have put x = 10. But it should be y = 10

So maybe you should start again from here with

and try to get x from that.

And think about the answer you get. y = 10 is between 20 and 4.5, so you should expect a year between 2001 and 2008.

Hope that helps,

Bob

Last edited by Bob (2011-05-29 01:42:34)

bobbym · 2011-05-29 01:51:42

Hi Bob;

zee is making that sort of error in every problem. Sometimes there are 1 of them per line. He/she is having algebraic difficulties with linear equations.

For instance post #44 is also incorrect. There the 10 is on the wrong side. There are numerous typos of the type of \ for / and B for b. Not only can teachers deduct points for this but when he tries to enter answers like that in online homework, they will not match.

I have been unable to stress that he/she is taking too many liberties with notation.

zee-f · 2011-05-29 02:02:33

thank alot am ganna be doing more exercise on this lesson then ill come back to it i thought am spouse to get rid of the 20 i mean thats what i learned and yup am having alot of problems with this lesson

bobbym · 2011-05-29 02:05:24

There is nothing wrong with having trouble. To remove a -20 you have to add a 20. That will get rid of it on that side.

zee-f · 2011-05-29 02:33:42

thanx am working on the problem

zee-f · 2011-05-29 04:13:46

17. Find the point-slope form of the equation that goes through these two points.
17- y-k=m(x-h)
y-20=-31\14X- -62031\14
y - 40 = ( - 31 / 14 ) x + (62031 / 14) 20
y=-31\14-62311\14

bobbym · 2011-05-29 04:22:57

Hi zee-f;

y-20=-31\14X- -62031\14

First thing is, this \ is not division. This / is division.

Add 20 to both sides.

And that is the answer.

zee-f · 2011-05-29 04:25:50

18. During which year was there 10 computers per student?
18- 10 =-31x\14- 62311\14
Ill get x=-62451\31

zee-f · 2011-05-29 04:27:44

wow that was simple i was doing something way more complicating

bobbym · 2011-05-29 04:30:15

That can not be right. Can you a negative year? Of course not.

That is the forumula you must use.

If the coordinate is ( 2001 , 20 ) that means x = 2001 and y = 20. So x is the year and y is the number of computers. So using this formula how do you substitute for x and y?

zee-f · 2011-05-29 04:36:19

y is ganna equal 10

zee-f · 2011-05-29 04:38:21

so i need to find x

bobbym · 2011-05-29 04:41:51

Yes, you will now solve.

Go slowly, 1 step per line.

zee-f · 2011-05-29 04:47:19

first i need to get the x by its self so ill subtract -31/14 from both sides isn't that correct

bobbym · 2011-05-29 04:52:28

Hi;

That is not legal and here is why. The -31 / 14 is connected to the x by multiplication not addition. To move values and variables from one side to another you use the inverse operation. This is simpler than that sounds.

First what I would do is clear the denominators by multiplying both sides by 14. Can you do that?

zee-f · 2011-05-29 05:13:59

yup

zee-f · 2011-05-29 05:15:51

140=-31x+ 62311/14

zee-f · 2011-05-29 05:17:16

now divide by -31

bobbym · 2011-05-29 05:23:39

Hold on!

140=-31x+ 62311/14

That is not correct. What about the 62311 / 14 ?

zee-f · 2011-05-29 05:36:55

so is it spouse to be 10=-31X-872354
or 140/31=31x-872354

bobbym · 2011-05-29 05:38:56

Not quite:

When you multiplied both sides by14 that means everything on both sides!

zee-f · 2011-05-29 05:41:58

10=-31x+62311

Math Is Fun Forum

#51 2011-05-29 01:26:13

Re: Point Slope Form of an Equation

#52 2011-05-29 01:27:46

Re: Point Slope Form of an Equation

#53 2011-05-29 01:30:56

Re: Point Slope Form of an Equation

#54 2011-05-29 01:41:40

Re: Point Slope Form of an Equation

#55 2011-05-29 01:51:42

Re: Point Slope Form of an Equation

#56 2011-05-29 02:02:33

Re: Point Slope Form of an Equation

#57 2011-05-29 02:05:24

Re: Point Slope Form of an Equation

#58 2011-05-29 02:33:42

Re: Point Slope Form of an Equation

#59 2011-05-29 04:13:46

Re: Point Slope Form of an Equation

#60 2011-05-29 04:22:57

Re: Point Slope Form of an Equation

#61 2011-05-29 04:25:50

Re: Point Slope Form of an Equation

#62 2011-05-29 04:27:44

Re: Point Slope Form of an Equation

#63 2011-05-29 04:30:15

Re: Point Slope Form of an Equation

#64 2011-05-29 04:36:19

Re: Point Slope Form of an Equation

#65 2011-05-29 04:38:21

Re: Point Slope Form of an Equation

#66 2011-05-29 04:41:51

Re: Point Slope Form of an Equation

#67 2011-05-29 04:47:19

Re: Point Slope Form of an Equation

#68 2011-05-29 04:52:28

Re: Point Slope Form of an Equation

#69 2011-05-29 05:13:59

Re: Point Slope Form of an Equation

#70 2011-05-29 05:15:51

Re: Point Slope Form of an Equation

#71 2011-05-29 05:17:16

Re: Point Slope Form of an Equation

#72 2011-05-29 05:23:39

Re: Point Slope Form of an Equation

#73 2011-05-29 05:36:55

Re: Point Slope Form of an Equation

#74 2011-05-29 05:38:56

Re: Point Slope Form of an Equation

#75 2011-05-29 05:41:58

Re: Point Slope Form of an Equation

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