Question

If 3x +4y is 16 and xy is 4 find 9x square + 16y square

Answer 1

hi!

here is your answer!

3x + 4y = 16 ...........................(given)

[By squaring both sides]

$({3x + 4y)}^{2} = {16}^{2}$


$9 {x}^{2} + 24xy + 16 {y}^{2} = 256$


Now, xy = 4 .....................(given)


$9 {x}^{2} + 16 {y}^{2} + 24(4) = 256$


$9 {x}^{2} + 16 {y}^{2} + 96 = 256$


$9 {x}^{2} + 16 {y}^{2} = 256 - 96$


$9 {x}^{2} + 16 {y}^{2} = 160$

$hope \: this \: \: helps\ .$