Find the value of following if a = 2 and b = – 2.(i) a2 – b2(ii)

1.	Find the value of following if a = 2 and b = – 2.(i) a2 – b2(ii) a2 – ab + b2(iii) a2 + b2
Answer» (i) In (a² – b²) put a = 2 and b = -2 a² – b² = (2)² – (-2) = 4 – 4 = 0 (ii) In (a² – ab + b²) put a = 2 and b = -2 a² – ab + b² = (2)² – 2x(-2) + (-2)² = 4 + 4 + 4 = 12 (iii) In a² + b² put a = 2 and b = -2 a² + b² = (2)² + (-2)² = 4 + 4 = 8

Find the value of following if a = 2 and b = – 2.(i) a2 – b2(ii) a2 – ab + b2(iii) a2 + b2

Answer»

(i) In (a² – b²) put a = 2 and b = -2
a² – b² = (2)² – (-2)
= 4 – 4 = 0

(ii) In (a² – ab + b²) put a = 2 and b = -2
a² – ab + b² = (2)² – 2x(-2) + (-2)²
= 4 + 4 + 4 = 12

(iii) In a² + b² put a = 2 and b = -2
a² + b² = (2)² + (-2)²
= 4 + 4 = 8