Ta có: \(\left(x+3\right)\left(x+5\right)\left(x+7\right)\left(x+9\right)+2033\)
\(=\left[\left(x+3\right)\left(x+9\right)\right]\left[\left(x+5\right)\left(x+7\right)\right]+2033\)
\(=\left(x^2+12x+27\right)\left(x^2+12x+35\right)+2033\)
\(=\left(x^2+12x+31-4\right)\left(x^2+12x+31+4\right)+2033\)
\(=\left(x^2+12x+31\right)^2-4^2+2033\)
\(=\left(x^2+12x+31\right)^2+2017\)
\(=\left(x^2+12x+31\right)^2-1^2+2018\)
\(=\left(x^2+12x+31-1\right)\left(x^2+12x+31+1\right)+2018\)
\(=\left(x^2+12x+30\right)\left(x^2+12x+32\right)+2018\)
Vì \(\left(x^2+12x+30\right)⋮\left(x^2+12x+30\right)\)
\(\Rightarrow\left(x^2+12x+30\right)\left(x^2+12x+32\right)⋮\left(x^2+12x+30\right)\)
\(\Rightarrow\left[\left(x^2+12x+30\right)\left(x^2+12x+32\right)+2018\right]:\left(x^2+12x+30\right)\) dư \(2018\)
\(\Rightarrow\left[\left(x+3\right)\left(x+5\right)\left(x+7\right)\left(x+9\right)+2033\right]:\left(x^2+12x+30\right)\)dư \(2018\)
Vậy số dư của phép chia\(\left(x+3\right)\left(x+5\right)\left(x+7\right)\left(x+9\right)+2033\)cho \(x^2+12x+30\)là \(2018\)
