Tìm x
3+4+7+10+...+133
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M=99-2:1+1=98
N=133-5:2+1=65
F=91-1:3+1=31
Q=402-2:4+1=101
So so hang: so cuoi - so dau : khoang cach +1
a) \((133-x):5=26\)
\(\implies 133-x=26\times5\)
\(\implies 133-x=130\)
\(\implies x=133-130\)
\(\implies x=3\). Vậy x=3.
b)\((3\times x-4):2-\frac{1}{4}=\frac{3}{4}\)
\(\implies (3\times x -4):2=\frac{3}{4}+\frac{1}{4}\)
\(\implies (3\times x -4):2=1\)
\(\implies 3\times x-4=2\)
\(\implies 3\times x=6\)
\(\implies x=2\). Vậy x=2.
c) \((2\times x-3)\times 3-5=10\)
\(\implies (2\times x-3)\times3 =10-5\)
\(\implies (2\times x-3)\times 3=5\)
\(\implies 2\times x-3=\frac{5}{3}\)
\(\implies 2\times x=\frac{5}{3}+3\)
\(\implies 2\times x=\frac{14}{3}\)
\(\implies x=\frac{14}{3}:2\)
\(\implies x=\frac{7}{3}\). Vậy \(x=\frac{7}{3}\)
a: x(2x-7)+14=4x
=>x(2x-7)-4x+14=0
=>x(2x-7)-2(2x-7)=0
=>(2x-7)(x-2)=0
=>\(\left[\begin{array}{l}2x-7=0\\ x-2=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=\frac72\\ x=2\end{array}\right.\)
b: \(25x^3=2x\)
=>\(25x^3-2x=0\)
=>\(x\left(25x^2-2\right)=0\)
TH1: x=0
=>x=0
TH2: \(25x^2-2=0\)
=>\(x^2=\frac{2}{25}\)
=>\(\left[\begin{array}{l}x=\frac{\sqrt2}{5}\\ x=-\frac{\sqrt2}{5}\end{array}\right.\)
c: \(\left(x-5\right)^3=x^3-125\)
=>\(x^3-15x^2+75x-125=x^3-125\)
=>\(-15x^2+75x=0\)
=>-15x(x-5)=0
=>x(x-5)=0
=>\(\left[\begin{array}{l}x=0\\ x-5=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=0\\ x=5\end{array}\right.\)
d: \(\left(x^3-x^2\right)-4x^2+8x-4=0\)
=>\(x^2\left(x-1\right)-4\left(x^2-2x+1\right)=0\)
=>\(x^2\left(x-1\right)-4\left(x-1\right)^2=0\)
=>\(\left(x-1\right)\left(x^2-4x+4\right)=0\)
=>\(\left(x-1\right)\left(x-2\right)^2=0\)
=>\(\left[\begin{array}{l}x-1=0\\ x-2=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=1\\ x=2\end{array}\right.\)
a: x(2x-7)+14=4x
=>x(2x-7)-4x+14=0
=>x(2x-7)-2(2x-7)=0
=>(2x-7)(x-2)=0
=>\(\left[\begin{array}{l}2x-7=0\\ x-2=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=\frac72\\ x=2\end{array}\right.\)
b: \(25x^3=2x\)
=>\(25x^3-2x=0\)
=>\(x\left(25x^2-2\right)=0\)
TH1: x=0
=>x=0
TH2: \(25x^2-2=0\)
=>\(x^2=\frac{2}{25}\)
=>\(\left[\begin{array}{l}x=\frac{\sqrt2}{5}\\ x=-\frac{\sqrt2}{5}\end{array}\right.\)
c: \(\left(x-5\right)^3=x^3-125\)
=>\(x^3-15x^2+75x-125=x^3-125\)
=>\(-15x^2+75x=0\)
=>-15x(x-5)=0
=>x(x-5)=0
=>\(\left[\begin{array}{l}x=0\\ x-5=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=0\\ x=5\end{array}\right.\)
d: \(\left(x^3-x^2\right)-4x^2+8x-4=0\)
=>\(x^2\left(x-1\right)-4\left(x^2-2x+1\right)=0\)
=>\(x^2\left(x-1\right)-4\left(x-1\right)^2=0\)
=>\(\left(x-1\right)\left(x^2-4x+4\right)=0\)
=>\(\left(x-1\right)\left(x-2\right)^2=0\)
=>\(\left[\begin{array}{l}x-1=0\\ x-2=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=1\\ x=2\end{array}\right.\)
làm giúp mk bài này nhá 0+1+2+...+2017 có bao nhiêu số hạng
a)x3-x2=0
⇔x2(x-1)=0
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)
b)3x2-5x=0
⇔ x(3x-5)=0
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{5}{3}\end{matrix}\right.\)
c)x3=x5
⇔ x3(1-x2)=0
⇔ x3(1-x)(1+x)=0
⇔\(\left[{}\begin{matrix}x=0\\x=1\\x=-1\end{matrix}\right.\)
d)(2x+7)2-4(2x+7)=0
⇔ (2x+7)(2x+3)=0
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-7}{2}\\x=\dfrac{-3}{2}\end{matrix}\right.\)
a) Ta có: \(x^3-x^2=0\)
\(\Leftrightarrow x^2\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)
b) Ta có: \(3x^2-5x=0\)
\(\Leftrightarrow x\left(3x-5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{5}{3}\end{matrix}\right.\)
c) Ta có: \(x^3=x^5\)
\(\Leftrightarrow x^5-x^3=0\)
\(\Leftrightarrow x^3\left(x^2-1\right)=0\)
\(\Leftrightarrow x^3\left(x-1\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\\x=-1\end{matrix}\right.\)
d) Ta có: \(\left(2x+7\right)^2-4\left(2x+7\right)=0\)
\(\Leftrightarrow\left(2x+7\right)\left(2x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-7}{2}\\x=\dfrac{-3}{2}\end{matrix}\right.\)
x đâu ông nội ????
khong co tim x
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