Question

If x + y = 8 and xy =15 , find x2 + y2.

Answer 1

to find x²+y²
applying identity
(x+y)²=x²+y²+2xy

x+y=8 (given),xy=15 (given)

(8)² =x² + y²+2(15)
64=x²+y² +30
64-30=x²+y²
34=x²+y²

Answer 2

♣ It is given that, ♣

x + y = 8 and xy = 15.

♣ To find ♣

The value of x² + y².

♣ Solution ♣

We know,

x² + y² = (x + y)² - 2xy

⇒x² + y² = (8)² - 2(15)

⇒x² + y² = 64 - 30

$\underline{\displaystyle{\sf{\huge\bold{\boxed{\red{\boxed{x^2+y^2=34}}}}}}}$