Factoring Trinomials & GCF

I'm stuck on these problems, can anyone help me? Thanks.

1. 8x^{3} - 56x^{2} + 80x

2.4v^{2} + 9v + 5

3. 5c^{2 } - 18c - 8

4. 56b^{2 } + 23b - 63

5. 6a^{4 } + 5a^{2} -25

6. 3b^{3} - 9b^{2} - 54b

Factoring GCF:

7.3x^{8} y^{6} + 6x^{6} y^{5} +24xy

Re: Factoring Trinomials & GCF

1: factor out 8x and then you have a quadratic left you can solve using the quadratic formula (when you know the zeros of your polynomial you know the factors)

2,3,4: directly apply quadratic formula

5: Let $\displaystyle x = a^2$ and you have a quadratic through which you can directly solve with the quadratic formula.

6: factor out 3b and then you have a quadratic left.

7: factor 3xy

For finding gcf it's mainly practice but in general if you have a polynomial, say $\displaystyle x^n*y^m + x^t*y^v$ factor out $\displaystyle x^a*y^b$ where $\displaystyle a = min (n,t)$ and $\displaystyle b = min(m,v)$