a) \(\left(\dfrac{3}{4}-81\right)\left(\dfrac{3^2}{5}-81\right)\left(\dfrac{3^3}{6}-81\right)...\left(\dfrac{3^{2000}}{2003}-81\right)\)
\(=\left(\dfrac{3}{4}-81\right)\left(\dfrac{3^2}{5}-81\right)...\left(\dfrac{3^6}{9}-81\right)...\left(\dfrac{3^{2000}}{2003}-81\right)\)
\(=\left(\dfrac{3}{4}-81\right)\left(\dfrac{3^2}{5}-81\right)...0...\left(\dfrac{3^{2000}}{2003}-81\right)=0\)
b) \(\left|x-2\right|=1\)
\(\Rightarrow\left[{}\begin{matrix}x-2=1\\x-2=-1\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)
Với x=3
\(6x^2+5x-2=6.3^2+5.3-2=67\)
Với x=1
\(6x^2+5x-2=6.1^2+5.1-2=9\)
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