Algebra practice question

Answer: A. 5

Expand: 6x − 3c = 6x − 15. The x-terms match, so the equation holds for every x exactly when 3c = 15, c = 5.

Why the other answers are wrong

B. −5

c = −5 gives 6x + 15 = 6x − 15, never true.

C. 15

c = 15 gives 6x − 45 = 6x − 15, never true.

D. No such value exists.

c = 5 makes both sides identical.

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