Bài 4:
a: \(2x^3-7x^2+5x+1\) ⋮2x-1
=>\(2x^3-x^2-6x^2+3x+2x-1+2\) ⋮2x-1
=>2⋮2x-1
mà 2x-1 lẻ
nên 2x-1∈{1;-1}
=>2x∈{2;0}
=>x∈{1;0}
b: \(\frac{3x^4-8x^3-10x^2+8x-5}{3x^2-2x+1}\)
\(=\frac{3x^4-2x^3+x^2-6x^3+4x^2-2x-15x^2+10x-5}{3x^2-2x+1}\)
\(=\frac{x^2\left(3x^2-2x+1\right)-2x\left(3x^2-2x+1\right)-5\left(3x^2-2x+1\right)}{3x^2-2x+1}=x^2-2x-5\)

