Answer:
the first choice 2 ; -2 ; 6 :-6
Step-by-step explanation:
1) method : you can put this values 2 ; -2 ; 6 :-6 you are 0
2) method you can solve this equation
x^4-40x^2+144=0
let : x² = t and t ≥ 0
t² -40t +144 = 0
Δ = b²- 4ac a= 1 b = - 40 c = 144
Δ =(-40)²- 4(1)(144= 1600 -576 = 1024=32²
t1 = (40+32)/2 = 36 = 6²
t1 = (40-32)/2 = 4 = 2²
but : x² = t and t ≥ 0
1)case : x² = 6² x = 6 or x= -6
2() case : x² =2² x = 2 or x= -2
