Respuesta :
5x - 2y + (7x - y).....x = 7 and y = -2
now we sub
5(7) - 2(-2) + (7(7) -(-2)
35 + 4 + (49 + 2)
35 + 4 + 51
90 <===
now we sub
5(7) - 2(-2) + (7(7) -(-2)
35 + 4 + (49 + 2)
35 + 4 + 51
90 <===
I was going to answer this question because I'm doing the same thing in Maths but it's already answered. He is correct though