Question

if 5x - 4y = 12 and xy = -3 find the value of ( 5x + 4y ) ^2​

Answer 1

Answer:

-96

Step-by-step explanation:

5x-4y=12

squaring on both sides

25x^2+16y^2-40xy=144

25x^2+16y^2-40(-3)=144

25x^2+16y^2=144-120

25x^2+16y^2=24

Solve : (5x+4y)^2

=25x^2+16y^2+40xy

=24+40(-3)

=24-120

=-96