Posted by **Alegebra2** on Friday, April 11, 2008 at 4:15pm.

Can someone check my answers for the following problems.

Simplify. Assume that no denominator equals 0.

1)(7x^2+3x-9)-(-x^2+8x-3)

answer: 6x^2-5x-6

2) 5x^3(7x)^2

answer: 245x^5

3) (2x-3)^2

answer: 4x^2-9

4) Use synthetic division to find (2x^3-5x^2+7x-1)/(x-1)

answer: 3

5)Identify the vertex,axis of symmetry, and direction of opening for y=2(x+3)^2-5

answer:

Axis of symmetry is x= -3/4

vertex -3/4

opens up

6) write y=-4x^2+8x-1 in vertex form

answer: (-4x+4)^2-17

- Troy -
**Damon**, Friday, April 11, 2008 at 6:34pm
1)(7x^2+3x-9)-(-x^2+8x-3)

answer: 6x^2-5x-6

now wait a minute

7 x^2 - ( -x^2) = 7 x^2 + x^2 = 8 x^2

agree with -5x-6

3) (2x-3)^2

answer: 4x^2-9

NO

(2x-3)(2x-3) = 4x^2-12 x + 9

now if you factor 4x^2 - 9 you get (2x-3)(2x+3)

- Troy -
**Damon**, Friday, April 11, 2008 at 6:37pm
4) Use synthetic division to find (2x^3-5x^2+7x-1)/(x-1)

answer: 3

Well I get a remainder of 3

2x^2 - 3 x + 4 and remainder of 3

- Troy -
**Damon**, Friday, April 11, 2008 at 6:40pm
5)Identify the vertex,axis of symmetry, and direction of opening for y=2(x+3)^2-5

answer:

Axis of symmetry is x= -3/4

vertex -3/4

opens up

===============

yes, opens up because as |x| gets big, y gets big +

(x+3) = 0 at x = -3

That is axis of symmetry

when x = -3

y = -5

so vertex at (-3,-5)

- Troy -
**Damon**, Friday, April 11, 2008 at 6:51pm
6) write y=-4x^2+8x-1 in vertex form

answer: (-4x+4)^2-17

y+1 = -4 x^2 + 8 x

-(y+1)/4 = x^2 - 2x

complete square by adding (-2/2)^2 to both sides

-(y+1)/4 + 1 = x^2 -2 x +1

-(y+1)/4 + 1 = (x-1)^2

(x-1)^2 = -y/4 -1/4 +4/4

(x-1)^2 = (-1/4)(y-3)

vertex (1,+3)

- Algebra2 -
**Troy**, Friday, April 11, 2008 at 7:29pm
For #1-3 I have to simplify them...and for #1 would it be 8x^2-5x-6 in the book it tells me to use the FOIL method.

- Troy -
**Damon**, Friday, April 11, 2008 at 11:13pm
and for #1 would it be 8x^2-5x-6

Yes

3) (2x-3)^2

answer: 4x^2-9

NO

(2x-3)(2x-3) = 4x^2-12 x + 9 <--- That is FOIL

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