Solve the system.
-xy = 20 x + y = 9
A) {(5, 4), (4, 5)}
B) {(-5, -4), (-4, -5)}
C) {(-5, 4), (-4, 5)}
D) {(5, -4), (4, -5)}

Question

Quizplus · Accepted Answer

The system of equations can be solved by substitution or elimination. From the second equation, y = 9 - x. Substituting this into the first equation gives x(9 - x) = 20, which simplifies to x^2 - 9x + 20 = 0. Factoring this quadratic equation gives (x - 5)(x - 4) = 0, so x = 5 or x = 4. Substituting these values back into y = 9 - x gives the pairs (5, 4) and (4, 5), which are the solutions to the system.

Solve the System. -Xy = 20 X + Y = 9