Question

if 4 x square + 9 y square equal to 69 and xy equal to 1 find the value of 2 X + 3 y

Answer 1

(2x + 3y)^2
= 4x^2 + 9y^2 + 2×2x × 3y
= 4x^2 + 9y^2 + 12xy
= 69 + 12×1
= 81
hence
(2x + 3y)^2 = 81
so
2x+3y = √81
2x + 3y = 9

Answer 2

2 X + 3 y^2

4 x^2 + 9 y^2 + 2 into 2 X into 3y .=4x^2+9y^2+2xy

=69+21*1=81

2 X + 3 y^2=81

2X + 3 y^2 =9^2

2x+3y=9