Question

Evaluate using the suitable identity.
(i) If + 1 =10 , find 2+ 1 2

Answer 1

Answer:

(a) (10x−1)

2

=(10x)

2

+(1)

2

−2×10x×1 (since (a−b)

2

=a

2

+b

2

−2ab)

=100x

2

−20x+1

(b) (x−8y)

2

=(x)

2

+(8y)

2

−2×x×8y ((a−b)

2

=a

2

+b

2

−2ab)

=x

2

−16xy+64y

2