`a)`` x^3+x^2=36` `->x^3+x^2-36=0`
`->x^3-3x^2+4x^2-12x+12x-36=0`
`->x^2(x-3)+4x(x-3)+12(x-3)=0`
`->(x-3)(x^2+4x+12)=0`
`->`\(\left[ \begin{array}{l}x-3=0\\x^2+4x+12=0\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x=3\\x^2+4x+4=-8\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x=3\\(x+2)^2=-8(KTM)\end{array} \right.\)
Vậy `S={3}`
`b)``10x^2-7=33x` `->10x^2-33x-7=0`
`->10x^2+2x-35x-7=0`
`->2x(5x+1)-7(5x+1)=0`
`->(5x+1)(2x-7)=0`
`->`\(\left[ \begin{array}{l}5x=-1\\2x=7\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x=\frac{-1}{5}\\x=\frac{7}{2}\end{array} \right.\)
Vậy `S={-1/5;7/2}`
