To figure out which ordered pair is a solution to the equation 3x + 5y = 9, substitute the coordinates of each answer choice into the equation. Remember that coordinates are written as (x, y) where the first number in the parentheses is x in the equation and the second number is y in the equation.
A. (-2, -3)
x = -2, y = -3
Substituting into the equation gives
3(-2) + 5(-3) = 9
-6 - 15 = 9
-21 = 9
This does not satisfy the equation, so (-2, -3) is not a solution.
B. (2, 3)
x = 2, y = 3
3(2) + 5(3) = 9
6 + 15 = 9
21 = 9
21 does not equal 9; therefore (2, 3) is not a solution.
C. (-2, 3)
x = -2, y = -3
3(-2) + 5(3) = 9
-6 + 15 = 9
9 = 9
This satisfies the equation, so (-2, 3) is a solution.
D. (2, -3)
x = 2, y = -3
3(2) + 5(-3) = 9
6 - 15 = 9
-9 = 9
This does not satisfy the equation; therefore (2, -3) is not a solution.
