3x + 2y = 42 and x = (1/2)y

Answer 1

x = y/2

2x = y

4x = 2y

4x - 2y = 0

3x + 2y = 42

add the 2 equations above to eliminate y

7x = 42

x = 42/7 = 6

2x = y = 12

x = 6, y = 12