Question

If 3x+2y = 12 and xy = 6 find the value of 9x square + 4y square

Answer 1

Given,
3x+2y=12 , xy=6

(3x+2y)^2 =12^2

=9x^2+4y^2+12xy=144

ie, 9x^2+4y^2+(12×6)=144
=9x^2+4y^2+72=144

9x^2+4y^2=144-72
=72.

Answer 2

If 3x+2y = 12

as well as xy = 6

then the value of 9x square + 4y square will be 3x+2y=12,

xy=6, (3x+2y)^2 =12^2 =9x^2+4y^2+12xy=144,

ie, 9x^2+4y^2+(12×6)=144 =9x^2+4y^2+72=144,

9x^2+4y^2=144-72 =72.

Finally your answer will be 72 as well as the value of 9x square + 4y square is 72.