Which expression can be simplified as 1/18n? (n2)9. (n^-9)-2. (n^-6)-3. (n^-6)-3. (n-3)^6

This is different from the first one can someone me

Given abcd ac=38 and ae=3x+4 find the value of x

Suzanne began a trip with 18 1/2 gallons of gas in the gas tank of her car if she hughes 17 3/4 gallons on the trip how many gallons does she have left once she finish the trip