what is a fifth of the sum of number a and 34
1/5 ( a+ 34) = a/5 + 34/5
1/5a + 34 = a/5 + 34
you missed 34a, when you distribute.
15⋅(a+34)=15⋅a+34⋅a
15⋅(a+34)=15⋅a+15⋅34