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SSC CPO 2019 PYQ — Question 119

SSC CPO Tier I - 13th December 2019 - Shift 2 • Quantitative Aptitude • Q119

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If x6 - 512y6 = (x2 + Ay2)(x4 - Bx2y2 + Cy4), then what is the value of (A + B - C):

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Correct answer: C

Explanation

The correct answer is Option 3 i.e. - 80

  Application
 

We know

a3 + b3 = (a + b)(a2 - ab + b2)

And

x6 - 512y6 can be written in the form of

{(x2)3 + (-8y2)3}

= {x2 + (-8y2)}(x4 - (-8x2y2) + 64y4)
 

Comparing with (x2 + Ay2)(x4 - Bx2y2 + Cy4):

A = - 8

B = - 8

C = 64

Hence,

(A + B - C) = - 8 - 8 - 64 = - 80