a) \(8x^2-6x^3=0\)
\(\Rightarrow2x^2\left(4-3x\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}2x^2=0\\4-3x=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{4}{3}\end{matrix}\right.\)
b) \(3x\left(x-4\right)-x\left(1+3x\right)=26\)
\(\Rightarrow3x^2-12x-x-3x^2=26\)
\(\Rightarrow-13x=26\)
\(\Rightarrow x=-2\)