4a*2-16
(3m-1)(3m+2)
y*2-y-6
(2a+4)(2a-4)
a*2-25
9m*2+3m-2
(y-3)(y+2)
(x-4)(x-2)
m*2+8m+7
x*2-6x+8
(a-b)(a+b)
(a+2)(a-3)
(m+1)(m+7)
a*2-a-6
(a+5)(a-5)
a*2-b*2
