compute x+y, given the linear system with T is not = to 1 and with the ordered pair (x,y) as solution: x+2y=3
and Tx+(T+1)y=T+2
multiply the first by T
Tx + 2Ty = 3T
Tx + (T+1)y = T+2
subtract ....
2Ty - (T+1)y = 3T - (T+2)
(T-1)y = 2T-2
y = 2(T-1)/(T-1) = 2
back in the first
x + 4 = 3
x = -1
then x+y = -1+2 = 1