Question

If x+y =10and xy=21,find 2(x²+y²)​

Answer 1

I hope it will help you

Answer 2

Answer:

x+y=10

(x+y)^2=10^2=x^2+y^2+2xy

therefore x^2 + y^2=x^2+y^2+2xy-2xy

therefore x^2+ y^2=(x+y)^2 -2xy

=100- 2(21)

=100-42

x^2+ y^2=58

2(x^2+ y^2)=58*2

=116