`#laviken#`
`a)`
`(3/4-81)(3^2/5-81)(3^3/6-81)...(3^2000/2003-81)`
`=(3/4-81)(3^2/5-81)...(3^6/9-81)...(3^2000.2003-81)`
`=(3/4-81)(3^2/5-81)..0...(3^2000.2003-81)`
`=0`
`b)|x-2|=1`
`=>`$\left[\begin{matrix} x-2=1\\ x-2=-1\end{matrix}\right.$
`=>`$\left[\begin{matrix} x=3\\ x=1\end{matrix}\right.$
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`
