Bài 3:
\(a,A=\left(x+2\right)^2:\left(x+2\right)=x+2=1998+2=2000\\ b,B=\left(2x-1\right)^3:\left(2x-1\right)^2=2x-1=2\cdot501-1=1001\\ c,C=\dfrac{27}{64}\left(x+3\right)^2=\dfrac{27}{64}\left(-2+3\right)^2=\dfrac{27}{64}\)
Bài 4:
\(a,A⋮B\Leftrightarrow2n\ge2\Leftrightarrow n\ge1\\ b,A⋮B\Leftrightarrow2n-2\ge4\Leftrightarrow n\ge3\)
