Answer:
3y - 5 + 2y = 7
Step-by-step explanation:
Subtracting 5 from the second equation gives ...
x = 3y -5
Using the expression on the right for x in the first equation gives ...
x + 2y = 7 . . . . . . . . first equation
(3y -5) +2y = 7 . . . . with expression substituted for x
3y - 5 + 2y = 7 . . . . with parentheses removed