3a^2+30ab+75ab=a^2=10ab+25b^2=(a+5)^2
27-c^3=(3-c)(9+3c+c^2)
xy-5y+x-5=(xy+x)-(5y+5)=x(y+1)-5(y+1)=(x-5)(y+1)
3a^2+30ab+75ab=a^2=10ab+25b^2=(a+5)^2
27-c^3=(3-c)(9+3c+c^2)
xy-5y+x-5=(xy+x)-(5y+5)=x(y+1)-5(y+1)=(x-5)(y+1)