Question

if x²+y²=9 andxy=8,then x+y is equal to?​

Answer 1

Answer:

x+y =root 1

Step-by-step explanation:

(x + y )squre 9

x2 + y2 + xy = 9

x2 + y2 + 8 = 9

x2 + y2 =8 -9

(x + Y )2 = 1

x + y =   root 1

Answer 2

Answer:

+ 5 , -5

Step-by-step explanation:

x² + y² = 9

Adding 2xy Both sides,

x² + y² + 2xy = 9 + 2xy .............. (1)

Given,

xy = 8

Putting Value of xy on equation (1)

x² + y² + 2xy = (x+y)²

so,

(x+y)² = 9 + 2xy

(x+y)² = 9 + 2 × 8

(x+y)² = 25

x+y = √25

Hence,

x+y = + 5 , - 5