Converting SEs into SoM and PoM

i'm a college student so this stuff is pretty basic (intro to digital design class) not sure if i am in the right forum to ask this but i need help with the following problems.

Problem 1: Convert following SEs into product of maxterms without obtaining sum of minterms first

xyz + yw + x'z' + xy'

So basically to do this we just keep expanding until we get a product of maxterms? like this..:

x(yz + y') + yw + x'z'
x(y' + z) + yw + x'z'
xy' + xz + yw + x'z'
(xy' + x)(xy' + z) + (yw+x')(yw+z')
x(xy'+z) + (yw+x')(yw+z')
(xy' +xz) + (yw+x')(yw+z')
((xy'+xz)) + (yw+x'))((xy'+xz) + (yw+z'))

I dont get what i do.. if i keep expanding it gets really complicated.. please advise.

thanks for your help.

Problem 2: Convert following SEs into sum of minterms
{[(a+b+a'c')c+d]' + ab'}
too much to type, but basically i got m(0,1,2,3,4,5,8,9,11,12) let me know if you agree with this if it disagrees ill type out what i have.

Check out pages 4-9 on this document. It should answer your questions.

"Minterms, Maxterms, and KMaps":http://www.cs.uiuc.edu/class/sp08/cs231/lectures/04-Kmap.pdf

Yeah this is really basic though. I just get stuck when I apply those concepts to this problem though. I need some guidance.