70 = 8t - 45

I'm assuming that the goal here is to solve for the only unknown variable, t. To do so, we need to isolate this variable, t, to one side of the equation by first adding 45 to both sides of the equation:

     70 + 45 = 8t - 45 + 45

          115 = 8t

Then we divide both sides of the equation by 8 to solve for t:

     115/8 = 8t/8

     115/8 = t

Thus,  t = 115/8 , which cannot be reduced any further.

70=8t -45     First:  Isolate the variable term, which in this case is "8t".  This can be done by adding 45 to both sides of the equation.   70+45=8t-45+45

                   Second:  Simplify.  70+45= 115     and -45+45=0

                   Third:  What we have now is  115=8t

                   Fourth:  Since the operation between the "8" and the "t" is multiplication, in order to get the "t" alone the reverse operation needs to be done.  The reverse operation of multiplication is division. 

115/8=8t/8 .  Now dividing both sides,  14.375= t  

                   Fifth:  It is a good habit to check your answers:  70= 8t -45

                                                                                       70= 8*115/8 -45  Note the 8's cancel

                                                                                       70= 115  -45

                                                                                        70=70  the answer checks