16Hit1600
AlgebraHardCoefficients from two intercepts

Algebra practice question

The graph of ax + by = 24 in the xy-plane has an x-intercept of 6 and a y-intercept of −3, where a and b are constants. What is the value of a + b?

Answer: -4

At (6, 0), 6a = 24 so a = 4; at (0, −3), −3b = 24 so b = −8; a + b = −4.

Common wrong answers

If you answered 4
4 is a alone.
If you answered 12
12 has b = 8, missing the negative y-intercept.
If you answered -2
−2 halves the answer.

More Algebra questions

Not affiliated with the College Board. SAT is a trademark of the College Board.