a: \(x^3-5x^2+8x-4\)
\(=x^3-2x^2-3x^2+6x+2x-4\)
\(=x^2\left(x-2\right)-3x\left(x-2\right)+2\left(x-2\right)\)
\(=\left(x-2\right)\left(x^2-3x+2\right)=\left(x-2\right)^2\cdot\left(x-1\right)\)
b: \(A⋮B\)
=>\(10x^2-7x-5⋮2x-3\)
=>\(10x^2-15x+8x-12+7⋮2x-3\)
=>\(7⋮2x-3\)
=>\(2x-3\in\left\{1;-1;7;-7\right\}\)
=>\(2x\in\left\{4;2;10;-4\right\}\)
=>\(x\in\left\{2;1;5;-2\right\}\)