Carcass wrote:
If (x – 3)(x + 2) = (x – 2)(x + 3), then x =
(A) –3
(B) –2
(C) 0
(D) 2
(E) 3
Great question!
I love that we can eliminate 4 answer choices
by inspection.
For example, if x =
3 (answer choice E), then we can see that we get: (
3 – 3)(
3 + 2) = (
3 – 2)(
3 + 3)
Simplify (in head) to get: (
ZERO)(non-zero #) = (non-zero #)(non-zero #)
This equation cannot hold true. So ELIMINATE E
Using the same logic we can also ELIMINATE A, B and D, which leaves us with C, the correct answer.
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The LONGER approach is to EXPAND and SOLVE
Given: (x – 3)(x + 2) = (x – 2)(x + 3)
Expand and simplify: x² - x - 6 = x² + x - 6
Add 6 to both sides to get: x² - x = x² + x
Subtract x² from both sides to get: -x = x
Add x to both sides: 0 = 2x
Solve: x = 0
Answer: C