If a2 + b2 + c2 = 2 (a – b – c) – 3 then the value of 2a – 3b + 4c is

As per the given question , we have
a² + b² + c² = 2 (a – b –c) –3
⇒ a² + b² + c² = 2a + 2b + 2c + 3 = 0
⇒ a² – 2a + 1 + b² + 2b + 1 + c² + 2c + 1 = 0
⇒ (a –1)² + (b + 1)² + (c + 1)² = 0
[If x² + y² + z² = 0 ⇒ x = 0; y = 0; z = 0]
∴ a – 1 = 0 ⇒ a = 1
b + 1 = 0 ⇒ b = – 1
c + 1 = 0 ⇒ c = – 1
∴ 2a – 3b + 4c = 2 + 3 – 4 = 1