Question 230510
x+y=18 or x=18-y
4x-7=2y+5
4(18-y)-7=2y+5
72-4y-7=2y+5
-4y-2y=5-72+7
-6y=-60
y=-60/-6
y=10 ans.
x=18-10
x=8 ans.
Proof:
4*8-7=2*10+5
32-7=20+5
25=25