Algebra practice question

Answer: -2 or −2

Simplify the left side: 8x − 2 − 5x = 3x − 2. For 3x − 2 = 3x + c to hold for every x, c must be −2.

Common wrong answers

If you answered 2

2 has the wrong sign: 2(4x − 1) contributes −2, not +2.

If you answered 8

8 is the coefficient 2 × 4 from the expansion, not the constant.

If you answered -1

−1 forgets to multiply the −1 inside the parentheses by 2.

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