If $x^{2} + y^{2} = 14$ and $x y = 3$ , find the value of:
$2 (x + y)^{2} - 5 (x - y)^{2}$

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Solution

Length = 2x + 1
Let breadth be x
Area $= l e n g t h \times b r e a d t h = x (2 x + 1) s q . u n i t s$
$2 (x + y)^{2} - 5 (x - y)^{2}$
$= 2 [x^{2} + y^{2} + 2 x y] - 5 [x^{2} + y^{2} - 2 x y]$
$= 2 [14 + 2 \times 3] - 5 [14 - 2 \times 3] = 2 [20] - 5 [8] = 40 - 40 = 0$

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Similar questions

If $x^{2}$ + $y^{2}$ = 14 and xy = 3, find the value of $2 {(x + y)}^{2} - 5 {(x - y)}^{2}$ .

If $x^{2} + y^{2} = 14$ and $x y = 3$ , find the value of $2 (x + y)^{2} - 5 (x - y)^{2}$ .

$If x^{2} + y^{2} = 14 and x y = 3,$
then find the value of
$2 (x + y)^{2} - 5 (x - y)^{2} .$

2 x + y = 14

x y = 6

4 x^{2} + y^{2}

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