Question

if x+y=9 and xy=20 then find x square +y square ​

Answer 1

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

=(9)^2-2×20

=81-40

=41

Answer 2

Given

x+y = 9

xy = 20

To Find

x²+y²

Solution

x²+y² = (x+y)² -2xy

x²+y² = (9)² -2(20)

x²+y² = 81 - 40

$\boxed{{x}^{2}+{y}^{2} = 40}$