Question

15. If x2 + y2 = 49 and xy = 16, then write the value of x + y.​

Answer 1

Answer:

value of (x + y) = 9

Step-by-step explanation:

given that :

x² + y² = 49

also xy = 16

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

let's square the value to be found

=(x + y)²

as we know that : (x + y)² = x² + y² + 2xy

= x² + y² + 2xy

substitute the values of (x² + y²) and xy in above equation

= (x² + y²) + 2(xy)

= (49) + 2(16)

= (49) + 32

= 81

so (x + y)² = 81;

( x + y ) = $\sqrt{81}$

(x + y) = $\sqrt{(9)(9)}$

(x + y) = 9

value of (x + y) = 9