a)5x(x-1)=x-1
5x(x-1)-(x-1)=0
(x-1)(5x+1)=0
\(\Rightarrow\left[\begin{array}{nghiempt}x-1=0\\5x+1=0\end{array}\right.\)\(\Rightarrow\)\(\left[\begin{array}{nghiempt}x=1\\x=\frac{-1}{5}\end{array}\right.\)
b)3x2-48x=0
6-48x=0
48x=6
x=6:48
x=\(\frac{1}{8}\)
c)x3+x2-4x=4
x3+x2-4x-4=0
x2.(x+1)-4.(x+1)=0
(x+1)(x2-4)=0
\(\Rightarrow\left[\begin{array}{nghiempt}x+1=0\\x^2-4=0\end{array}\right.\)\(\Rightarrow\)\(\left[\begin{array}{nghiempt}x=-1\\x=2;-2\end{array}\right.\)
a) 5x(x-1)=x-1
<=>5x(x-1)-(x-1)=0
<=>(x-1)(5x-1)=0
<=>x-1=0 hoặc 5x-1=0
+) x-1=0<=>x=1
+)5x-1=0<=> x=1/5
b) \(3x^2-48x=0\)
\(\Leftrightarrow3x\left(x-16\right)=0\)
\(\Leftrightarrow3x=0\) hoặc x-16=0
+) x=0
+)x-16=0<=>x=16
c) \(x^3+x^2-4x=4\)
\(\Leftrightarrow x^3+x^2-4x-4=0\)
\(\Leftrightarrow x^2\left(x+1\right)-4\left(x+1\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(x^2-4\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(x-2\right)\left(x+2\right)=0\)
\(\Leftrightarrow x+1=0\) hoặc \(x-2=0\) hoặc \(x+2=0\)
+) x+1=0<=>x=-1
+)x-2=0<=>x=2
+)x+2=0<=>x=-2
1, \(5x\left(x-1\right)=x-1\)
\(\Leftrightarrow5x=\frac{x-1}{x-1}\)
\(\Leftrightarrow5x=1\)
\(\Leftrightarrow x=\frac{1}{5}\)
2, \(3x^2-48x=0\)
\(\Leftrightarrow3x\left(x-16\right)=0\)
\(\Leftrightarrow x-16=0\)
\(\Leftrightarrow x=16\)
3, \(x^3+x^2-4x-4=0\)
\(\Leftrightarrow x^2\left(x+1\right)-4\left(x+1\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(x^2-4\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x+1=0\\x^2-4=0\end{array}\right.\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=-1\\x^2=4\end{array}\right.\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=-1\\\hept{\begin{cases}x=2\\x=-2\end{array}\right.\end{array}\right.\)
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