Упростите выражения
1) (a+1)(a*2-a+1)-a*3


2) (x+y)(x*2-xy+y*2)-x(x*2+y*2)


3) (m-2)(m*2+2m+4)+8

4) (c+3)(c*2-3c+9)-27​

1) (a+1)(a*2-a+1)-a*3 =а^3+1-а^3=1

2) (x+y)(x*2-xy+y*2)-x(x*2+y*2) =х^3+х^2у-х^2у-ху^2+ху^2+у^3-х^3-ху^2=у^3-ху^2

3) (m-2)(m*2+2m+4)+8 =m^3-2m^2+2m^2-4m+4m-8+8=m^3

4) (c+3)(c*2-3c+9)-27=c^3+27-27=c^3