1) Each term has two things in common! They're all divisible by -2, and they're all divisible by n. Hence they're all divisible by -2n. So that's your factor!

This gives . This can be further factorised by letting and considering the quadratic!

By the quadratic equation hence is the only factor! Hence

Hence the entire expression is

2) Use the quadratic equation to solve the equation . You should get a single root . This means that is a factor. And this the discriminant is zero, in fact TWO of these are factors. Hence the answer is

3) Notice that this can be written as . This can be written