Question

[°𝗝𝗲𝘆シ︎°]

1/ 3(x - 1) - 5(x - 2) = 4(x + 1)

2/ -2(x - 2) - 4(x + 1) = -3(x + 3)  

3/ 3x\(^2\) + 2x = 0

4/ x\(^2\) - 5x = 0

5/ (2x - 3)\(^2\) = 36

6/ (5x - 1)\(^3\) = 125

7/ 3\(^x\) + 1 = 27

Answer 1

[Nguyễn Lê Phước Thịnh]

1) Ta có: \(3\left(x-1\right)-5\left(x-2\right)=4\left(x+1\right)\)

\(\Leftrightarrow3x-5-5x+10-4x-4=0\)

\(\Leftrightarrow-6x+1=0\)

\(\Leftrightarrow-6x=-1\)

hay \(x=\dfrac{1}{6}\)

2) Ta có: \(-2\left(x-2\right)-4\left(x+1\right)=-3\left(x+3\right)\)

\(\Leftrightarrow-2x+4-4x-4+3x+9=0\)

\(\Leftrightarrow-3x=-9\)

hay x=3

3) Ta có: \(3x^2+2x=0\)

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

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-\dfrac{2}{3}\end{matrix}\right.\)

4) Ta có: \(x^2-5x=0\)

\(\Leftrightarrow x\left(x-5\right)=0\)

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

5) Ta có: \(\left(2x-3\right)^2=36\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-3=6\\2x-3=-6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=9\\2x=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{2}\\x=-\dfrac{3}{2}\end{matrix}\right.\)

Answer 2

[Nguyễn Lê Phước Thịnh]

6) Ta có: \(\left(5x-1\right)^3=125\)

\(\Leftrightarrow5x-1=5\)

\(\Leftrightarrow5x=6\)

hay \(x=\dfrac{6}{5}\)

7) Ta có: \(3^{x+1}=27\)

\(\Leftrightarrow x+1=3\)

hay x=2