Need math help with factoring polynomials

1- Factor by grouping.
xy−3x+3y−9

2- Factor the following polynomials by grouping the terms together two at a time.
24x^2+6x−28x−7

3- Factor the following polynomials by grouping the terms together two at a time.
16x^3−4x^2−20x+5

4- Factor the following by taking out the greatest common factor.
8x^3+32x^2

5- Factor by grouping.
xy+7x−6y−42

6- Factor the following polynomials by grouping the terms together two at a time.
x^3+4x^2−6x−24

7- Factor the following by taking out the greatest common factor.
132a^4−11b^4

Ps: no need to explain