If A = 2a2 – 4b – 1; B = 5a2 + 3b – 8 and C = 2a2 – 9b + 3

1.	If A = 2a2 – 4b – 1; B = 5a2 + 3b – 8 and C = 2a2 – 9b + 3 then find the value of A – B + C.
Answer» Given A = 2a² – 4b – 1; B = 5a² + 3b – 8; C = 2a² – 9b + 3 A – B + C = (2a² – 4b – 1) – (5a² + 3b – 8) + (2a² – 9b + 3) = 2a² – 4b – 1 + (-5a² – 3b + 8) + 2a² – 9b + 3 = 2a² – 4b – 1 – 5a² – 3b + 8 + 2a² – 9b + 3 = 2a² – 5a² + 2a² – 4b – 3b – 9b – 1 + 8 + 3 = (2 – 5 + 2)a² + (-4 – 3 – 9)6 + (-1 + 8 + 3) = -a² – 16b + 10

If A = 2a2 – 4b – 1; B = 5a2 + 3b – 8 and C = 2a2 – 9b + 3 then find the value of A – B + C.

Answer»

Given A = 2a² – 4b – 1; B = 5a² + 3b – 8; C = 2a² – 9b + 3

A – B + C = (2a² – 4b – 1) – (5a² + 3b – 8) + (2a² – 9b + 3)

= 2a² – 4b – 1 + (-5a² – 3b + 8) + 2a² – 9b + 3

= 2a² – 4b – 1 – 5a² – 3b + 8 + 2a² – 9b + 3

= 2a² – 5a² + 2a² – 4b – 3b – 9b – 1 + 8 + 3

= (2 – 5 + 2)a² + (-4 – 3 – 9)6 + (-1 + 8 + 3)

= -a² – 16b + 10