review

bobbym · 2011-08-20 11:08:15

Hi;

zee-f · 2011-08-20 11:13:38

oooh ok so u factored the 4x

12- Factor x^2 + 9x + 14 by grouping. Be sure to factor completely and show your work. If this is not possible for some reason, state why.

12- x^2+9x+14
X^2*14=14x : 7*2
X^2+7x+2x+14
X(x+7)+2(x+7)
(x+2)(x+7)

bobbym · 2011-08-20 11:24:35

That is correct but you sometimes are using X for x. You should pick one and stick with it for the problem. In math they have different meanings.

zee-f · 2011-08-20 11:29:21

i acutely used x but because i had it written in Microsoft words and am coping my work so yeah it posted it as capitalized i missed that

Last edited by zee-f (2011-08-20 11:50:12)

zee-f · 2011-08-20 11:31:57

hey i was wondering what is the difference between the X and x in math ?

bobbym · 2011-08-20 11:33:05

X is used in statistics and probability. x is used everywhere else.

zee-f · 2011-08-20 11:36:36

oooh ok

zee-f · 2011-08-20 11:38:01

this is the rest of the work i did .......

13. Factor 4x^6 16x^2 using the difference of squares method. Be sure to factor completely and show your work. If this is not possible for some reason, state why.

13- 4x^6-16x^2= (2x^3-4x)(2x^3+4x)

14. Factor x^2 + 16x + 64 by using the perfect squares method. Be sure to factor completely and show your work. If this is not possible for some reason, state why.

14- x^2+16x+64

Square root of x^2=x
Square root of 64=8
8*x=8x
8x isnt equivalent to 16x so I can't factor it as a perfect square.

15. Factor x^2 + 9 using any method you choose. Show your work. If this is not possible for some reason, state why.

15- x^2=x*x

9=3*3

(x^2+9)

(x+3)(x+3)

16. Solve -3x2 - 9x + 12 = 0.
-3*12=-36 (-12+3)
-3x^212x+3x+12
[(-3x^2-(-12x)]+[(3x+12)]

-3x(x+4)+3(x+4)
(-3x+3)(x+4)
X=1 x=-4

bobbym · 2011-08-20 11:44:33

For 13) are you saying you can only use the difference of 2 squares?

zee-f · 2011-08-20 11:49:25

nope it can be factored differently but my question is asking me to do it using the difference of squares method

bobbym · 2011-08-20 11:51:06

Hi;

Oh, okay I got what you mean.

zee-f · 2011-08-20 11:55:05

Hi;

yup, did i factor it wrong ?

bobbym · 2011-08-20 11:56:39

I am not sure she will go for 13)? We will have to see.

14) Is incorrect.

zee-f · 2011-08-20 12:01:05

hey for 14 i used this site
http://www.ehow.com/how_5953961_factor-polynomials-perfect-squares.html

i did as the instructions said

bobbym · 2011-08-20 12:05:48

zee-f · 2011-08-21 01:57:55

so did i do the instructions wrong

bobbym · 2011-08-21 02:55:45

Hi zee-f;

Hmmm, that is a square. So try the instructions again.

zee-f · 2011-08-21 09:44:10

hey i corrected what i did wrong

x^2+16x+64

Square root of x^2=x
Square root of 64=8

Multiply x times 8 times 2 and get 16x

Which is the same number as my middle term so I can continue so my answer is going to be (d+e)^2 where d is my square root of x^2 and e is the square root of 64 which is 8

Answer is (x+8)^2

bobbym · 2011-08-21 09:53:43

Yep! That is correct.

zee-f · 2011-08-21 10:33:32

heres the rest of what i did i was wondering if there correct

15. Factor x^2 + 9 using any method you choose. Show your work. If this is not possible for some reason, state why.

15- x^2=x*x

9=3*3

(x^2+9)

(x+3)(x+3)

16. Solve -3x^2 - 9x + 12 = 0.
-3*12=-36 (-12+3)
-3x^212x+3x+12
[(-3x^2-(-12x)]+[(3x+12)]

-3x(x+4)+3(x+4)
(-3x+3)(x+4)
x=1 x=-4

17. Solve x^2 - x = 56

x^2-x=56

-56+-1x+x^2=0

(-7+-1x)(8+-1x)=0

-7+-1x=0+7

-7+-1x

-1x=7

x=-7

8+-1x=0

-1x=0-8

-1x=-8

x=8

x=-7,8

zee-f · 2011-08-21 10:35:44

and for this image uploaded 18-

roots are -1,1

(x+1)(x-1)=

x^2-x-1

19. The product of two consecutive positive integers is 42. Write and solve a quadratic equation to find the numbers.

19- x^2+x=42

0=x^2+x-42
42-x+x^2=0

(x+7)(x-6)=0

x=6
Or -7
x=6
x+1=7 so x=6 and 7

Last edited by zee-f (2011-08-21 11:26:39)

bobbym · 2011-08-21 11:43:52

15) Is incorrect.

zee-f · 2011-08-22 02:40:54

for 15 it is not possible, it is the sum of squares. right ?

bobbym · 2011-08-22 03:47:36

Hi;

zee-f · 2011-08-22 07:31:17

ooh ok so what did earlier was correct ? right (x^2+9)

(x+3)(x+3)
??

Math Is Fun Forum

#51 2011-08-20 11:08:15

Re: review

#52 2011-08-20 11:13:38

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#53 2011-08-20 11:24:35

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#54 2011-08-20 11:29:21

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#56 2011-08-20 11:33:05

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