Question

If 3x+2y=12 andxy=2 find the value of 9x2+4x2

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.