1a (a-b)²=a²-2ab+b²
(3m-4k)²=3²*m²-2*4*3*m*k+4²*k²=9m²-24mk+16k²
1b (a+b)²=a²+2ab+b²
1c (a-b)(a+b)=a²-b²
(4d-13)(4d+13)=16d²-169
1d (a-b)(a+b)=a²-b²
=9xy⁵-16x³y³=xy³(9y²-16x²)=xy³(3y-4x)(3y+4x)
2a
4x²-9y²=(2x-3y)(2x+3y)
2b
27-8m³=(3-2m)(9+6m+4m²)
2c
-3p²-6p-3=-3(p²+2p+1)=-3(p+1)²