1) (x-6)(x+6)
2)(0,5-c)(0,5+c)
3)(12-m)(12+m)
4)(5y-7)(5y+7)
5)(11b-c)(11b+c)
6)(4x-9y)(4x+9y)
7)(cd-a)(cd+a)
8)(ab-3y)(ab+3y)
9)49x²-81
10)b²-16a²
