Find a+b+c, given that x + y is not equal to -1 and
ax + by + c = x + 7
a + bx + cy = 2x + 6y
ay + b + cx = 3x - 1.
Add the equations and we have
(a + b + c )x + (a + b + c)y + (a + b + c) = 6x + 6y + 6
Equating terms....(a + b + c) = 6
