Question

If x squared + 1 upon x squared = 79, find x + 1 upon x

Answer 1

x²+1/x²=79(given),    x+1/x=???
(x+1/x)²=x²+1/x²+2
(x+1/x)²=79+2
(x+1/x)²=81
x+1/x=√81=9
 ⇒    Hence x+1/x=9