Question

If X + 2Y=8 and XY=2; find the value of x^2+ 4 y^2

Answer 1

Answer:

56

Step-by-step explanation:

Solve this using the formula (a+b)^2=a^2+b^2+2ab

Let a be x

And let b be 2y

(x+2y)^2 =x^2+(2y) ^2+2*x*2y

8^2= x^2+4y^2+4*2

x^2+4y^2=64-8

=56

Answer 2

Step-by-step explanation:

Since, X+2Y=8 & XY=2

Y/2+2Y =8

(Y+4Y)/2=8

5Y=16

Y= 16/5

& X= 2×(5/16) = 5/8

Therefore

x^2+4y^2 = (5/8)^2 + 4×(16/5)^2

= 25/64 + 4(256/25)

= calculate