giúp mình bài 33b với ạ
\(\left(x-3\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2+3x^2=-33\)
\(x^3-3x^23+3x3^2-3^3-\left(x^3-3^3\right)+6\left(x^2+2x+1\right)+3x^2=-33\)
\(x^3-9x^2+3x9-27-\left(x^3-27\right)+6x^2+12x+6+3x^2=-33\)
\(x^3-9x^2+27x-27-x^3+27+6x^2+12x+6+3x^2=-33\)
\(\left(x^3-x^3\right)+\left(6x^2-9x^2+3x^2\right)+\left(27x+12x\right)+\left(27-27+6\right)=-33\)
\(39x+6=-33\)
\(39x=-33-6\)
\(39x=-39\)
\(x=-1\)
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