a) Use synthetic division:
For the divisor, the form is x-a, so for x+1 we have a=-1:
-1 | 1 -2 -7 18 -18
| -1 3 4 -22
|____________________
1 -3 -4 22 -40 --> Remainder is -40
b) If x=1-i is a root, then too must be x=1+i as complex roots always come in conjugate pairs.... and now we can divide:
--> x=-3 and x=3 are also zeros
c) Part (b) has the four factors, using real valued polynomials: