Question

If x-1/2=4 then x^2+1/x^2=?

Answer 1

I think you did mistake in typing
question may be ,
x + 1/x = 4 then, find x² +1/x² ?

you know,
(a + b)² = a² + b² + 2ab
(a + b)² - 2ab = a² + b² use this concept here,

(x + 1/x)² - 2.x.1/x = x² + 1/x²
(x + 1/x)² -2 = x² + 1/x²
put (x + 1/x) = 4 here,

(4)² -2 = x² + 1/x²
x² + 1/x² = 16 -2 = 14