Question

Given that xy = 36 and x - y = 5, Find the value of x² + y².​

Answer 1

First you must find two numbers that times to 36 and minus to give you 5, I have found 9 and 4. Next you can square 9 and 4 to give you 81 and 16. Add them together and you should get the answer 97. Hope this helps :)

Answer 2

97

Explanation:

To find x² + y², use the identity (x - y)² = x² + y² - 2xy.

(x - y)² = x² + y² - 2xy

Substitute xy = 36 and x - y = 5 in the above formula,

5² = x² + y² - 2*36

25 = x² + y² - 72

Add 72 to both sides,

25 + 72 = x² + y²

x² + y² = 97