Solve the system of equations. −5x+4y=3x=2y−15x equals y equals

Question

Answer:

Note: in the 2nd eqn we are given a formula for x: x = 2y-15. Sub this result into the first eqn; doing so will eliminate x:

-5(2y-15)+4y =3

-10y + 75 + 4y = 3, so -6y = -72. Then y = 12. Solution is (9,12).

Check this by subst.:

Is -5(9)+4(12) = 3?
Is -45 + 48 = 3? YES.