Question

systemof equations for x+2y=7, 6x-6y=15

Answer 1

from the 1st: x = 7-2y

into the 2nd:
6(7-2y) - 6y = 15
42 - 12y - 6y = 15
-18y = -27
y = 3/2
into x = 7-2y
x = 7 - 3 = 4

x = 4, y = 3/2