Question 279694
Can you please assist me with this problem.
Find all real solutions of the equation. 
 
(x^2+1)^2 - 18(x^2+1) = - 17.  substitute x^2+1 by a

a^2-18a+17=0

a^2-17a-a+17=0

a(a-17)-1(a-17)=0

(a-17)(a-1)=0

(x^2+1-17)(x^2+1-1)

(x^2-16)*x^2

x^2(x+4)(x-4)