caranya nomor 10-11 gimana? tolong dijawab

10) [x²-1] < 3
= x²-1-3<0
= x²-4 <0
= [x-2] [x+2]
x¹ = 2,x²= -2
jadi {x | x ≥ 2 atau x ≤ -2}. E