Question bank / Linear equations in one variable

Math · AlgebraMedium

The equation 34(8x−12)=2(x+k)\frac{3}{4}(8x - 12) = 2(x + k), where kk is a constant, has the solution x=5x = 5. What is the value of kk?

Student-produced response: enter your answer.

Show answer and explanation

Answer: 11/2

Substitute x=5x = 5. The left side is 34(40−12)=34(28)=21\frac{3}{4}(40 - 12) = \frac{3}{4}(28) = 21. The right side is 2(5+k)=10+2k2(5 + k) = 10 + 2k. So 10+2k=2110 + 2k = 21, which gives 2k=112k = 11 and k=5.5k = 5.5.

Forgetting to multiply kk by 22 gives 10+k=2110 + k = 21 and k=11k = 11.

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, or take a free full-length practice test.