Troy
posted by Alegebra2 on .
Can someone check my answers for the following problems.
Simplify. Assume that no denominator equals 0.
1)(7x^2+3x9)(x^2+8x3)
answer: 6x^25x6
2) 5x^3(7x)^2
answer: 245x^5
3) (2x3)^2
answer: 4x^29
4) Use synthetic division to find (2x^35x^2+7x1)/(x1)
answer: 3
5)Identify the vertex,axis of symmetry, and direction of opening for y=2(x+3)^25
answer:
Axis of symmetry is x= 3/4
vertex 3/4
opens up
6) write y=4x^2+8x1 in vertex form
answer: (4x+4)^217

1)(7x^2+3x9)(x^2+8x3)
answer: 6x^25x6
now wait a minute
7 x^2  ( x^2) = 7 x^2 + x^2 = 8 x^2
agree with 5x6
3) (2x3)^2
answer: 4x^29
NO
(2x3)(2x3) = 4x^212 x + 9
now if you factor 4x^2  9 you get (2x3)(2x+3) 
4) Use synthetic division to find (2x^35x^2+7x1)/(x1)
answer: 3
Well I get a remainder of 3
2x^2  3 x + 4 and remainder of 3 
5)Identify the vertex,axis of symmetry, and direction of opening for y=2(x+3)^25
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) 
6) write y=4x^2+8x1 in vertex form
answer: (4x+4)^217
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 = (x1)^2
(x1)^2 = y/4 1/4 +4/4
(x1)^2 = (1/4)(y3)
vertex (1,+3) 
For #13 I have to simplify them...and for #1 would it be 8x^25x6 in the book it tells me to use the FOIL method.

and for #1 would it be 8x^25x6
Yes
3) (2x3)^2
answer: 4x^29
NO
(2x3)(2x3) = 4x^212 x + 9 < That is FOIL