Question 73687
x+y=115
x-y=21 x=y+21 now substitute (y+21) for xin the first equation.
(y+21)+y=115
y+y=115-21
2y=94
y=94/2
y=47 answer. no solve for x
x-47=21
x=47+21
x=68 answer.
proof
47+68=115
115=115