\(P=\left(x+2\right)\left(x+4\right)\left(x+6\right)\left(x+8\right)+2040\)
\(=\left(x^2+10x+16\right)\left(x^2+10x+24\right)+2040\)
\(=\left(x^2+10x+21-5\right)\left(x^2+10x+21+3\right)+2040\)
\(=\left(x^2+10x+21\right)^2-2\left(x^2+10x+21\right)-15+2040\)
\(=Q^2-2Q+2025\)
=>P chia Q sẽ dư 2025