Question

I need to know how to solve these problems because i do nkt understand them

Answer 1

So, for this kind of problem you need to FOIL. 
This stands for:
F- first
O-outer
I-inner
L-last

What this means is that:
step 1- multiply the FIRST terms in each thing. So for example in problem 6 of the problems you sent it would be x times x.  = $x^{2}$
step 2- multiply the OUTER terms in each thing. So for example in problem 6, it would be x times 3.  =3x
step 3- multiply the INNER terms in each thing. So for example in problem 6, it would be 6 times x.  =6x
step 4- multiply the LAST terms in each thing. So for example in problem 6, it would be 6 times 3.  =18
step 5: you add all of your products. So for problem 6 it would be y= $x^{2}$ + 9x +18.