Replace y in the second equation with y from the first one:
2x + 15-5x = 12
Combine like terms:
15-3x = 12
Subtract 15 from both sides:
-3x = -3
Divide both sides by -3:
X = 1
now you know x, solve for y using the first equation.
Y = 15 -5(1) = 15 -5 = 10
Y = 10
Answer( x = 1 and y = 10
