CUET Preparation Today
CUET
General Test
Quantitative Reasoning
Algebra
If a = 1021, b = 1020, c = 1018, then
find a2 + b2 + c2 - ab - bc - ca.
4
5
7
9
a2 + b2 + c2 - ab - bc - ca = 12 [(a - b)2 + (b - c)2 + (c - a)2]
= 12 [(1021 - 1020)2 + (1020 - 1018 )2 + (1018 - 1021)2]
= 12 [1 + 4 + 9] = 7
