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\(A=\left[x^2-1\right]\cdot\left[x^2-2\right]\cdot\left[x^2-3\right]\cdot...\cdot\left[x^2-2013\right]\)
Với x = 5 ta có : \(A=\left[5^2-1\right]\cdot\left[5^2-2\right]\cdot\left[5^2-3\right]...\left[5^2-2013\right]\)
\(A=\left[25-1\right]\left[25-2\right]\left[25-3\right]...\left[25-2013\right]\)
\(A=24\cdot23\cdot22\cdot...\cdot\left[-1988\right]\)
Tính nốt :v
a: Sửa đề: \(\dfrac{2x-1}{11}+\dfrac{2x-2}{12}+\dfrac{2x-3}{13}=\dfrac{2x+5}{5}+\dfrac{2x+7}{3}+\dfrac{2x+4}{6}\)
\(\Leftrightarrow\dfrac{2x-1}{11}+1+\dfrac{2x-2}{12}+1+\dfrac{2x-3}{13}+1=\dfrac{2x+5}{5}+1+\dfrac{2x+7}{3}+1+\dfrac{2x+4}{6}+1\)
=>2x+10=0
hay x=-5
b: \(\dfrac{x-1}{2016}+\dfrac{x-2}{2015}+\dfrac{x-3}{2014}+\dfrac{x-4}{2013}+\dfrac{x-5}{2012}-5=0\)
\(\Leftrightarrow\left(\dfrac{x-1}{2016}-1\right)+\left(\dfrac{x-2}{2015}-1\right)+\left(\dfrac{x-3}{2014}-1\right)+\left(\dfrac{x-4}{2013}-1\right)+\left(\dfrac{x-5}{2012}-1\right)=0\)
=>x-2017=0
hay x=2017
a: Sửa đề: \(\dfrac{2x-1}{11}+\dfrac{2x-2}{12}+\dfrac{2x-3}{13}=\dfrac{2x+5}{5}+\dfrac{2x+7}{3}+\dfrac{2x+4}{6}\)
\(\Leftrightarrow\dfrac{2x-1}{11}+1+\dfrac{2x-2}{12}+1+\dfrac{2x-3}{13}+1=\dfrac{2x+5}{5}+1+\dfrac{2x+7}{3}+1+\dfrac{2x+4}{6}+1\)
=>2x+10=0
hay x=-5
b: \(\dfrac{x-1}{2016}+\dfrac{x-2}{2015}+\dfrac{x-3}{2014}+\dfrac{x-4}{2013}+\dfrac{x-5}{2012}-5=0\)
\(\Leftrightarrow\left(\dfrac{x-1}{2016}-1\right)+\left(\dfrac{x-2}{2015}-1\right)+\left(\dfrac{x-3}{2014}-1\right)+\left(\dfrac{x-4}{2013}-1\right)+\left(\dfrac{x-5}{2012}-1\right)=0\)
=>x-2017=0
hay x=2017
1: =>x=1 và y=1
3: =>x-0,2=0 và y+0,1=0 và x+y+z=0
=>x=0,2; y=-0,1; z=-x-y=-0,2+0,1=-0,1
Để ý ta có:
M=(x^2-1)(x^2-2)(x^2-3)...(x^2-25)...(x^2-2013)
Thay x=5,ta đc
M=(5^2-1)(5^2-2)(5^2-3)...(5^2-25)...(5^2-2013)
=(5^2-1)(5^2-2)(5^2-3)...0....(5^2-2013)=0 vậy M=0
Nhớ tik