Question bank / Systems of two linear equations in two variables

Math · AlgebraMedium

In the xyxy-plane, the line y=mx+4y = mx + 4, where mm is a constant, intersects the line y=2x−1y = 2x - 1 at the point where x=5x = 5. What is the value of mm?

Student-produced response: enter your answer.

Show answer and explanation

Answer: 1

At x=5x = 5, the second line gives y=2(5)−1=9y = 2(5) - 1 = 9. So (5,9)(5, 9) is on the first line: 9=5m+49 = 5m + 4, so m=1m = 1.

Assuming the lines have the same slope gives m=2m = 2, but then they would never intersect.

Ask Owl about this questionNext question

Got it wrong? On SAT Owl, Owl looks at the answer you chose and explains the exact mistake, then gives you similar questions until it sticks. Get your predicted SAT score free.