Question

If x+y=5 , xy=4 find x^2+y^2

Answer 1

Step-by-step explanation:

(x + y)^2 = 5^2

X^2 + y^2 +2xy = 25

X^2 +y^2 +8 =25

X^2 + y^2 =25-8

X^2 + y^2 = 17

Answer 2

x^2 + y^2 =?

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

(5)^2 = x^2 + y^2 +2xy

25 = x^2 + y^2 + 2× 4

25 = x^2 + y^2 + 8

25-8 = x^2 + y^2

so , x^2 + y^2 = 17