Algebra practice question

Answer: 1.6 or 8/5

m has slope −1/2 and y-intercept 5: y = −x/2 + 5. Solving 2x + 1 = −x/2 + 5 gives 5x/2 = 4, so x = 8/5.

Common wrong answers

If you answered 2

2 uses slope −1 for m instead of −1/2.

If you answered 4

4 solves 2x + 1 = −x/2 + 5 without dividing by 5/2.

If you answered -4

−4 uses a parallel line of slope 2 through (0, 5), which never meets ℓ; the sign is a guess.

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