Question

If x + y is 9 and xy = 14 then find x2+ y2
.

Answer 1

Answer:

x2 + y? + 2xy = 196

x? + y? = 196 - 2(14)

x? + y? = 168 =

Yto *491 l 75%

Remove 2xy from both sides,

x2 + y? - 2xy = 168 - 2(14)

(x - y)2 = 140

X - y = v140

Hence,

x² - y²

=> (x + y) (x - y)

=> (9)(/140)

=> 9-V(2x2x35)

=> 18 V35