j)
(x+2)^4=81
(x+2)^4=3^4
x+2=3
x=3-2
x=1
k)
(x^2+1)^2=16
(x^2+1)^2-16=0
(x^2+1)^2-4^2=0
(x^2+1+2)(x^2+1-2)=0
(x^2+3)(x^2-1)=0
x^2+3=0
x^2=-3| Sprzeczne
lub
z^2-1=0
x^2=1
x_1=\sqrt1
x_2=-\sqrt1
l)
(x^2-7)^3=-125
(x^2-7)^3=(-5)^3
x^2-7=-5
x^2=-5+7
x^2=2
x_1=\sqrt2
x_2=-\sqrt2