Question

Ifx-y= 7 and x2+y2=169, find the value of x y . hence find(x+y).​

Answer 1

Step-by-step explanation:

x - y = 7

x² + y² = 196

( x - y ) ² = x² + y² - 2xy

7² = 196 - 2xy

2xy = 196 - 49

xy = 147 / 2

xy = 73.5

( x + y )² = x² + y² + 2xy

( x + y ) ² = 196 + 73.5 × 2

x + y = √ 196 + 147

x + y = ±√ 343

x + y = ± 7√7