Question

If (x + y) = 6 and xy =3, find the value of x2 + y2.

Answer 1

Answer:

30

Step-by-step explanation:

(x+y)²=x²+y²+2xy

36=x²+y²+6

30=x²+y²

Answer 2

Given:

I) x+y=6

II) xy=3

Solution:

From the identity,

$(x+y)^{2} = x^{2} +2xy+y^{2}$

$(6)^{2}$ $=x^{2} +2(3)+y^{2}$

$36=6+x^{2} + y^{2}$

$30 =x^{2} +y^{2}$

∴ $x^{2} +y^{2}=30$