Answer :
{ x + y = 56
{ y = x + 4
x + y = 56
x + ( x + 4 ) = 56
x + x = 56 - 4
2x = 52
x = 52
2
x = 26
x + y =56
26 + y = 56
y = 56 - 26
y = 30
S = { 26 , 30 }
{ y = x + 4
x + y = 56
x + ( x + 4 ) = 56
x + x = 56 - 4
2x = 52
x = 52
2
x = 26
x + y =56
26 + y = 56
y = 56 - 26
y = 30
S = { 26 , 30 }