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Find the value of a2+b2+c2−2ab+2ac−2bca^2+ b^2+ c^2-2ab + 2ac- 2bca2+b2+c2−2ab+2ac−2bc​, if a = x + y, b = x - y and c = 2x - 1
Question

Find the value of a2+b2+c22ab+2ac2bca^2+ b^2+ c^2-2ab + 2ac- 2bc​, if a = x + y, b = x - y and c = 2x - 1

A.

0

B.

(2x+2y1)2(2x+2y-1)^2​​

C.

(2x2y1)2(2x-2y-1)^2​​

D.

(xy1)2(x-y-1)^2​​

Correct option is B

Given:

a = x + y,

b = x - y, 

c = 2x - 1
Formula Used:

(a - b)² = a² + b² - 2ab
Solution:

=> a² + b² + c² - 2ab + 2ac - 2bc

=>(x + y)² + (x - y)² + (2x - 1)² - 2(x + y)(x - y) + 2(x + y)(2x - 1) - 2(x - y)(2x - 1)

=>x² + 2xy + y² + x² - 2xy + y² + 4x² - 4x + 1 - 2(x² - y²) + 4x(2x - 1) - 4y(2x - 1)

=>6x² + 2y² - 4x + 1 - 2x² + 2y² + 8x² - 4x - 8xy + 4y

=>2x² + 4y² - 8x + 5

=>(2x)² + (2y)² - 2×2x×2y + 5

=>(2x - 2y)² + 5

=> (2x + 2y - 1)²

Thus, the correct answer is (b).

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