halpz pliz

0

493

5

If (2x+3y)^2 = 4 and xy = -5, what is the value of 4x^2 + 9y^2

Guest Oct 9, 2020

0 users composing answers..

5⁺⁰ Answers

+37146

+1

(2x+3y)^2 = 4 expand

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

4 x^2 + 12(-5) + 9y^2 = 4 You can take it from here, hopefully !

ElectricPavlov Oct 9, 2020

0

well i got that already i got 4x + 9y = 64 but i dont understand how to turn this into 4x^2 + 9y^2 = something?

Guest Oct 9, 2020

+37146

+1

Well, if you got 4x + 9y = 64 you didn't look at the answer I gave you......

ElectricPavlov Oct 9, 2020

0

Ok i got it right thank you! i understood my mistake was i forgot that when simplifying (2x+3y)(2x+3y) i just multiplyed out the integers but i forgot that the variables also square each other.

Guest Oct 9, 2020

+37146

0

Yay !

ElectricPavlov Oct 9, 2020

2 Online Users