x + 5y = 7

x + 5y-5y = 7-5y

x= 7-5y

x + 3y = 1

7-5y + 3y = 1

7-2y= 1

7-2y-7= 1-7

-2y=-6

-2y/-2=-6/-2

y=3

x= 7-5(3)

x= 7-15=-8