Question

Bài 5: Tìm x (Giải phương trinh)

a)x^3-13x=0

 b) 5x(x – 2000) – x + 2000 = 0

c) 2x(x – 2) + 3(x – 2) = 0 

d) x + 1 = (x + 1)2

e) x + 5x2 = 0

f) x3 + x = 0

Bài 5: Tìm x (Giải phương trình)

a)x^3-13x=0 b) 5x(x – 2000) – x + 2000 = 0

c) 2x(x – 2) + 3(x – 2) = 0 d) x + 5x2 = 0

d) x + 1 = (x + 1)2 e) x3 + x = 0

 

 

 

Answer 1

b) 5x(x-2000)-x+2000=0

\(\Rightarrow5x\left(x-2000\right)-\left(x-2000\right)=0\\ \Rightarrow\left(x-2000\right)\left(5x-1\right)=0\)

\(\Rightarrow\left\{{}\begin{matrix}x-2000=0\\5x-1=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0+2000\\5x=0+1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=2000\\5x=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=2000\\x=\dfrac{1}{5}\end{matrix}\right.\)

Answer 2

Ai giúp minh làm bài 5 phía trên với

 

Answer 3

c) Ta có: \(2x\left(x-2\right)+3\left(x-2\right)=0\)

\(\Leftrightarrow\left(x-2\right)\left(2x+3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{-3}{2}\end{matrix}\right.\)

d) Ta có: \(5x^2+x=0\)

\(\Leftrightarrow x\left(5x+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{-1}{5}\end{matrix}\right.\)