Question 39363
1:Factor out by GCF 4x^2 + 36y^2
=4(x^2+9y^2)

2:Factor by grouping 3x^2 - 12x + 5x -20
=3x(x-4)+5(x-4)
=(x-4)(3x+5)

3:Factor completely 9x^2 - 16y^2
=(3x-4y)(3x+4y)

4:factor completely 3x^2 - 2x - 8
=3x^2-6x+4x-8
=3x(x-2)+4(x-2)
=(x-2)(3x+4)

5:Factor completely 3x^2 + 12x + 12
=3(x^2+4x+4)
=3(x+2)^2

Cheers,
Stan H.