I'll do 14 and 18, and you can apply those techniques for the other problems!
For 14, we get 30*(1/10^8). This means that you move the decimal place in 00.0000030.0 seven places to the left, resulting in 0.00000300
For 18, we can use the associative property of multiplication to get
5*3.5*10^3*10^(-1)=17.5*10^2. We get 10^2 by adding 3 and -1 up. Since it's positive 2, we simply move the decimal 2 places to the right to get 1750