GMAT Practice Question: If x is not equal to -1/2, then 6x^3+3 x^2-8x-4/2x+1=
Question
If x is not equal to -1/2, then 6x^3+3 x^2-8x-4/2x+1=
- 3 x^2+3/2 x-8
- 3 x^2+3/2 x-4
- 3 x^2-4
- 3 x-4
- 3 x+4
Topics: factoring, equations with unknowns in the denominator
Solution
Step 1
We group the numerator into two pairs to set up factoring.
6x^3 + 3x^2 - 8x - 4 = 3x^2(2x+1) - 4(2x+1)
Step 2
We factor out the common binomial from each group.
3x^2(2x+1) - 4(2x+1) = (2x+1)(3x^2 - 4)
Step 3
We remove the common factor since 2x+1 is nonzero under the given condition.
(2x+1)(3x^2 - 4)(2x+1) = 3x^2 - 4
Answer
3x^2 - 4
