1) \(\left(x+3\right)^3-8=\left(x+3\right)^3-2^3=\left(x+3-2\right)\left[\left(x+3\right)^2+\left(x+3\right).2+2^2\right]=\left(x+1\right)\left(x^2+6x+9+2x+6+4\right)=\left(x+1\right)\left(x^2+8x+19\right)\)2) \(x^3+12x^2+48x+64=x^3+3.x^2.4+3.x.4^2+\left(4\right)^3=\left(x+4\right)^3\)