b) [x(x+1)/(x²-1)]=(x+1)/(x²-1)
x(x²-1)(x+1)=(x+1)(x²-1)
x(x²-1)(x+1)-(x²-1)(x+1)=0
(x²-1)(x+1)(x-1)=0
(x+1)(x-1)(x+1)(x-1)=0
x₁=-1
x₂=1
x₃=-1
x₄=1
x∈{-1,1}
b) t/(t²-1)=t/(t+1)
t(t+1)=t(t²-1)
t²+t=t³-t
-t³+t²+t+t=0
-t³+t²+2t=0 inmultim-1
t³-t²-2t=0
t(t²-t-2)=0
t₁=0
t²-t-2=0
Δ=1+8=9
t₂=(1-3)/2=-2/2=-1
t₂=-1
t3=(1+3)/2=4/2=2
t₃=2
t∈{-1,0,2}