I need help answering number 4.7

Please show steps.

I know the answer from the solution manual but I need to know how it was derived!

4.7 Repeat problem 4.1 for the function f(x1,,x5)=m(1,4,6,7,9,10,12,15,17,19, 20,23,25,26,27,28,30,31)+D(8,16,21,22). *4.1 Find the minimum-cost SOP and POS forms for the function f(x1,x2,x3)=m(1,2,3,5)