Algebra practice question

Answer: A. 15

Tripling the first equation gives 15x − 6y = 30, which must match the second, so k = 15.

Why the other answers are wrong

B. 5

5 keeps the first equation's coefficient without scaling by 3.

C. 3

3 is the scale factor, not k.

D. −15

−15 has the wrong sign.

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