find the value of f(2),f(-2).

Compare this with f(x). This means subbing x=2 into the bracket.

"state one of the factors of f(x)"

If it is a factor of f(x), it will not have any remainder.

therefore, for eg. when u sub x=-2 into f(x),

f(x)=2x^3+13x^2+13x-10

f(-2)=2{(-2)^3} +13{(-2)^2}+13(-2)-10=Remainder=0

This means (x+2) is a factor of f(x)