10(t-4)= 5(2t-8) Use the distributive principle: 10t-40 = 10t-40 <--- you can tell from here that it is an identity since both sides are identical. Add 40 to both sides: 10t = 10t Subtract 10t from both sides: 0t = 0 There are infinitely many solutions because 0t = 0 is true for any value of t. Edwin