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If a = 7 + √2, b = 7 - √2, then what is the value of a² + b²?
Question

If a = 7 + √2, b = 7 - √2, then what is the value of a² + b²?

A.

104

B.

100

C.

102

D.

98

Correct option is C

Given:
a = 7+27 + \sqrt{2}​​
b = 727 - \sqrt{2}​​
Formula Used:
(a+b)2+(ab)2=2×(a2+b2)(a + b)^2 + (a - b)^2 = 2 × (a^2 + b^2)​​
Solution:
We need to find the value of a2+b2.a^2 + b^2.​​
Substitute the given values into the algebraic identity format directly.
(7+2)2+(72)2(7 + \sqrt{2})^2 + (7 - \sqrt{2})^2  

=2×(72+(2)2)= 2 × (7^2 + (\sqrt{2})^2) 

= 2 ×( 49 + 2) 

= 2 × 51

= 102
Final Answer
So the correct answer is (c)

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