Question

If x2 + y2 = 9 and
and xy = 8, then x + y is equal to​

Answer 1

Answer:

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

or,(x+y)^2=9+2*8

or,(x+y)^2=25

or,(x+y)=5

Answer 2

Answer:

value of (x + y) = 5

Step-by-step explanation:

it is given that :

x² + y² = 9

and xy = 8

we have to find the value of (x + y)

let's square it: (x + y)²

we know that;

(x + y)² = x² + y² + 2xy

so substitute values of (x² + y²) and 'xy' in above equation :

(x + y)² = 9 + 2(8)

= 9 + 16 = 25

so value of  (x + y)² = 25

but value of (x + y) = $\sqrt{25}$

=$\sqrt{(5)(5)}$

= 5

value of (x + y) = 5