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Examveda

If p(x + y)2 = 5 and q(x - y)2 = 3 then the simplified value of p2(x + y)2 + 4pqxy - q2(x - y)2 is:

A. 2(p + q)

B. -(p + q)

C. -2(p +q)

D. p + q

Answer: Option A

Solution(By Examveda Team)

$$\eqalign{ & p{\left( {x + y} \right)^2} = 5{\text{ and }}q{\left( {x - y} \right)^2} = 3 \cr & {\text{Put the value of }}x = 2{\text{ and }}y = 1 \cr & p{\left( {2 + 1} \right)^2} = 5{\text{ and }}q{\left( {2 - 1} \right)^2} = 3 \cr & p = \frac{5}{9},\,q = 3 \cr & \to {p^2}{\left( {x + y} \right)^2} + 4pqxy - {q^2}{\left( {x - y} \right)^2} \cr & = {\left( {\frac{5}{9}} \right)^2}{\left( {2 + 1} \right)^2} + 4 \times \frac{5}{9} \times 3 \times 2 \times 1 - {\left( 3 \right)^2}{\left( {2 - 1} \right)^2} \cr & = \frac{{25}}{{81}} \times 9 + \frac{{40}}{3} - 9 \cr & = \frac{{25}}{9} + \frac{{40}}{3} - 9 \cr & = \frac{{25 + 120 - 81}}{9} \cr & = \frac{{64}}{9} \cr & {\text{Put the value of }}p{\text{ and }}q{\text{ in option A}} \cr & {\text{option A }} \to {\text{2}}\left( {p + q} \right) \cr & = 2\left( {\frac{5}{9} + 3} \right) \cr & = 2 \times \frac{{32}}{9} \cr & = \frac{{64}}{9} \cr & {\text{Option A is satisfied}} \cr & {\text{So, 2}}\left( {p + q} \right)\,{\text{is answer}} \cr} $$

This Question Belongs to Arithmetic Ability >> Algebra

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