a:=6x^2+4x-6x^2-9x
=-5x
b: =x^3+6x^2+12x+8+x^3-9x^2+27x-27-x^3-5x^2
=x^3-8x^2+39x-19
c: =x^-4/3x+2
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a)
\(2x\left(3x+2\right)-3x\left(2x+3\right)\\ =6x^2+4x-6x^2-9x\\ =6x^2-6x^2+4x-9x\\ =-5x\)
b)
\(\left(x+2\right)^3+\left(x-3\right)^2-x^2\left(x+5\right)\\ =x^3+6x^2+12x+8+x^2-6x+9-x^3-5x^2\)
\(=x^3-x^3+6x^2+x^2-5x^2+12x-6x+8+9\)
\(=2x^2+6x+17\)
c)
\(\left(3x^3-4x^2+6x\right):3x=x^2-\dfrac{4}{3}x+2\)
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