a) Solving for t:
We isolate our unknown t on one side, to leave the factors of t on one side and the numbers on the other:
-1st step: substract 17 from both sides --> 5t = -15
-2nd step: divide by 5 on both sides --> t = -3
b) Solving for x: We now isolate the power of x on one side:
-1st step: add x^3 on both sides --> 2*(x^3)-25=103
-2nd step: add 25 on both sides --> 2*(x^3) = 128
-3rd step: divide by two on both sides --> x^3 = 64