Question: 107 x 107 + 93 x 93 = ?
[A].19578
19418
20098
21908
[A].
[B].
[C].
[D].
Answer: Option C
Explanation:
107 x 107 + 93 x 93 | = (107)2 + (93)2 |
= (100 + 7)2 + (100 – 7)2 | |
= 2 x [(100)2 + 72] [Ref: (a + b)2 + (a – b)2 = 2(a2 + b2)] | |
= 20098 |