\(5x^3-2x\left(x^2-3x\right)-3x\left(x^2-1\right)=3x+24\)
\(\Leftrightarrow5x^3-2x^3+6x^2-3x^3+3x=3x+24\)
\(\Leftrightarrow5x^3-5x^3+6x^2+3x-3x=24\)
\(\Leftrightarrow6x^2=24\)
\(\Leftrightarrow x^2=4\)
=> x=2 hoặc x=-2
b) \(6x\left(x-5\right)+3x\left(7-2x\right)=18\)
\(6x^2-30x+21x-6x^2=18\)
\(6x^2-6x^2-30x+21x=18\)
-9x=18
=> x=-2
c) \(2x\left(3x+1\right)+\left(4-2x\right)3x=7\)
\(6x^2+2x+12x-6x^2=7\)
\(6x^2-6x^2+2x+12x=7\)
14x=7
\(\Rightarrow x=\dfrac{1}{2}\)
a, \(5x^3-2x^3+6x^2-3x^3+3x=3x+24\Leftrightarrow6x^2=24\Leftrightarrow x^2=4\Leftrightarrow x=\pm2\)
b, \(6x^2-30x+21x-6x^2=18\Leftrightarrow-9x=18\Leftrightarrow x=-2\)
c, \(6x^2+2x+12x-6x^2=7\Leftrightarrow14x=7\Leftrightarrow x=\dfrac{1}{2}\)
a.
<=> \(5x^3-2x^3+6x^2-3x^3+3x-3x-24=0\)
<=> \(6x^2-24=0\)
<=> \(6x^2=24\)
=> \(x^2=\dfrac{24}{6}=4\)
=> \(x=\pm2\)
