Question

Simplify:
-12x^4
x^4+8x^5

A -12 ; x ≠-1/8
1+8x
B -12 ; x ≠ -1/8, 0
1+8x
C -12 ; x ≠ 0
9x
D -12
9

Simplify:
x
7x+x^2

A 1 ; x ≠ -7
7+x
B 1 ; x ≠ 0
7x
C 1 ; x ≠ 0,-7
7+x
D 1
7

Simplify:
x-2
x^2+4x-12

A 1 ; x ≠ -6
x+6
B 1 ; x ≠ -6,
x+6
C 1 ; x ≠ -2
x+2
D x+2

Simplify:
x^2-3x-18
x+3

A x-3
B x-6 ; x ≠ -3
C x-6 ; x ≠ 6
D 1 ; x ≠ -3
x+3

Answer 1

If you factor each of them and then set your answer = 0 you will be able to pick out a multiple choice answer that fits each scenerio.
You try them...
Submit your answers...
and we will check them : )
For example x^2 - 3x - 18 = (x -6)(x+3)

Answer 2

For example, the first one:
-12x^4 / (x^4+8x^5)
= -12x^4 / (x^4(1+8x))

division by zero is undefined, so B is the right choice
why not A? Because the original fraction is 0/0 if x=0

You need to type your fractions as I did, rather than trying to copy/paste into plain text.