You don't! There are no common factors.
(x + 5)(x + 1)
x(x + 23)
(3t + 1)(t + 5)
7(3y-2)-(-4y+9)
3x(2x + 1)
(b + 2c)(b - c)
Until an "equals" sign shows up somewhere in the expression, there's nothing to prove.
(x - 2)(2x - 3)
the answer is (3x-2)(9x squared+6x+4)
(x + 3)(x + 2)
x2 + 6x + 8 =(x + 2)(x +4)