the given expressions are,
2x + y = 9 ........(1)
3x - y = 16 .........(2)
Add both the equation,
2x + 3x + y - y = 9 + 16
5x + 0 = 25
5x = 25
x = 25/5
x = 5
put x = 5 in equation (1)
2(5) + y = 9
10 + y = 9
y = 9 - 10
y = -1
thus, the answer is x = 5 and y = -1
