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,(8x-3).(3x+2)-(4x+7).(x+4)=(2x+1).(5x-1)-33 đúng không bạn

a)\(2x^4-6x^3+x^2+6x-3=0\)

\(\Leftrightarrow2x^4-6x^3+3x^2-2x^2+6x-3=0\)

\(\Leftrightarrow x^2\left(2x^2-6x+3\right)-\left(2x^2-6x+3\right)=0\)

\(\Leftrightarrow\left(x^2-1\right)\left(2x^2-6x+3\right)=0\)

\(\Leftrightarrow\left(x-1\right)\left(x+1\right)\left(2x^2-6x+3\right)=0\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x-1=0\\x+1=0\\2x^2-6x+3=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=1\\x=-1\\\Delta_{2x^2-6x+3}=\left(-6\right)^2-4\left(2.3\right)=12\end{array}\right.\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x=1\\x=-1\\x_{1,2}=\frac{6\pm\sqrt{12}}{4}\end{array}\right.\)

b)\(x^3+9x^2+26x+24=0\)

\(\Leftrightarrow x^3+5x^2+6x+4x^2+20x+24=0\)

\(\Leftrightarrow x\left(x^2+5x+6\right)+4\left(x^2+5x+6\right)=0\)

\(\Leftrightarrow\left(x^2+5x+6\right)\left(x+4\right)=0\)

\(\Leftrightarrow\left(x+2\right)\left(x+3\right)\left(x+4\right)=0\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x+2=0\\x+3=0\\x+4=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=-2\\x=-3\\x=-4\end{array}\right.\)

\(-4x\left(x-5\right)-2x\left(8-2x\right)=-3\)

\(\Leftrightarrow-4x^2+20x-16x+4x^2=-3\)

\(\Leftrightarrow4x=-3\Leftrightarrow x=\frac{-3}{4}\)

dễ cực cho mình **** đi mình giải cho

\(\frac{x}{4}=\frac{y}{3}\Rightarrow\frac{x}{12}=\frac{y}{9}\)

\(\frac{x}{3}=\frac{z}{5}\Rightarrow\frac{x}{12}=\frac{z}{20}\)

\(\Rightarrow\frac{x}{12}=\frac{y}{9}=\frac{z}{20}=\frac{2x-3y+z}{2\cdot12-3\cdot9+20}=\frac{6}{17}\)

\(\Rightarrow x=\frac{72}{17};y=\frac{54}{17};z=\frac{120}{17}\)