Question 84 (vi)
Simplify
(2.5m+1.5q)2+(2.5m−1.5q)2
We have,
(2.5m+1.5q)2+(2.5m−1.5q)2=(2.5m)2+(1.5q)2+2×2.5m×1.5q+(2.5m)2+(1.5q)2−2×(2.5m)×(1.5q)
[using the identities, (a+b)2=a2+b2+2ab and (a−b)2=a2+b2−2ab]
=6.25m2+2.25q2+6.25m2+2.25q2=(6.25+6.25)m2+(2.25+2.25)q2=12.5m2+4.5q2