Replace the unknown number as x. You know that (x-3.2)1/4=1.8. Multiply (x-3.2)1/4 by four to cancel out the 1/4 and do the same with 1.8 on the other side. This will leave you with x-3.2=7.2. Add +3.2 to both sides of the equation to cancel out the -3.2 and it leaves you with x=10.4. Your answer is 10.4
