Question

Find the following squares by suing the identities.

(i) ( 2/3m + 3/2n )²

(ii) ( 0.4p - 0.5q )²

(iii) ( 2xy + 5y )²

Answer 1

(i) 

            [(a + b)² = a² + 2ab + b²]

= 4/9m² + 2mn + 9/4n²

(v) (0.4p − 0.5q)² 

= (0.4p)² − 2 (0.4p) (0.5q) + (0.5q)²   [(a − b)² = a² − 2ab + b²]

= 0.16p² − 0.4pq + 0.25q²

(vi) (2xy + 5y)² 

= (2xy)² + 2(2xy) (5y) + (5y)²   [(a + b)² = a² + 2ab + b²]

= 4x²y² + 20xy² + 25y²