find three consecutive integers whose sum is 126.
A= lowest number
B = middle number
C = biggest number
A + 2 = C
A = C - 2 Call kthis eq1
B + 1 = C
B = C - 1 Call this eq2
A + B + C = 126 Call this eq3
Substitute eq1 eq2 to eq3
(C - 2) + C - 1) + C = 126
3C - 3 = 126
3C = 126 + 3
C = 129/3
C = 43
In eq2
B = C - 1
B = 42
In eq1
A = C - 2
A = 41