Algebra practice question

Answer: 2

Slopes: −k/2 and −2/k. Parallel means −k/2 = −2/k, so k² = 4 and k = 2 (positive). With k = 2 the lines are y = −x + 3 and y = −x + 4, which are distinct.

Common wrong answers

If you answered 1

1 gives slopes −1/2 and −2, which are not equal.

If you answered 4

4 is k², not k.

If you answered -2

−2 also makes the slopes equal but is not positive.

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