(x^2-5)^2-3(x^2-5)-4=0

Question

(x^2-5)^2-3(x^2-5)-4=0

Answer 1

(x^2-5)^2-3(x^2-5)-4=0
x^2-5=t
t^2-3t-4=0
D=9-4*(-4)*1=16+9=25
t1,2= 3+/-5/2
t_1 = 4 ; t_2 = -1
x^2-5=4 ; x^2 =9 x=+-3
x^2-5=-1 x^2=4 x=+-2
(x=+-2; x=+-3)