a. \(\left(x-3\right)\left(x+3\right)-2\left(x+3\right)=0\Leftrightarrow\left(x+3\right)\left(x-5\right)=0\Leftrightarrow x=-3;x=5\)
b, \(-\left(x^3-3x^2+3x-1\right)=0\Leftrightarrow-\left(x-1\right)^3=0\Leftrightarrow x=1\)
c, \(4x^2-20x+25-4\left(x^2-1\right)=x^3-1-x^3-2x\)
\(\Leftrightarrow-20x+29=-1-2x\Leftrightarrow-18x=-30\Leftrightarrow x=\dfrac{30}{18}=\dfrac{5}{3}\)


