***ANSWER ASAP****Use synthetic division to solve (x^3-x^2-17x-15)/(x-5)

There's nothing to "solve" here; "solve" only applies to equations. Rather, you're expected to divide or simplify.

5  |  1   -1   -17   -15
.   |        5    20     15
- - - - - - - - - - - - - - - -
.   |  1    4      3       0

which translates to

[tex]\dfrac{x^3-x^2-17x-15}{x-5}=x^2+4x+3[/tex]