With s=t−1 we have s3=t3−3t2+3t−1, and the first equation can be written as x=s3+1. From the second equation we get 27(s3)4=(x2−1)3, hence, by taking cube roots, 3s4=x2−1, i.e. x2=3s4+1. Comparing with the square of x=s3+1 we obtain
3s4+1=s6+2s3+1, or
s6−3s4+2s3=0,i.e.
s3(s−1)2(s+2)=0.
So, s=−2,0,1, i.e., t=s+1=−1,1,2 and x=s3+1=−7,1,2. The three solutions (t,x) are (−1,−7), (1,1) and (2,2).