Question

If 2x+3y=8 and xy=4 find 4x^2+9y^2

Answer 1

Step-by-step explanation:

2x+3y=8

By squaring both sides.

(2x+3y)^2=8^2

By using identity : (a+b) ^2=a^2+b^2+2ab

4x^2+9y^2+12xy =64

4x^2+9y^2+12(4)=64

4x^2+9y^2+48=64

4x^2+9y^2=64-48

4x^2+9y^2=16