* Trả lời:

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

\(\Leftrightarrow-3+6x-4-12x=-5x+5\)

\(\Leftrightarrow6x-12x+5x=3+4+5\)

\(\Leftrightarrow x=12\)

\(\left(2\right)\) \(3\left(2x-5\right)-6\left(1-4x\right)=-3x+7\)

\(\Leftrightarrow6x-15-6+24x=-3x+7\)

\(\Leftrightarrow6x+24x+3x=15+6+7\)

\(\Leftrightarrow33x=28\)

\(\Leftrightarrow x=\dfrac{28}{33}\)

\(\left(3\right)\) \(\left(1-3x\right)-2\left(3x-6\right)=-4x-5\)

\(\Leftrightarrow1-3x-6x+12=-4x-5\)

\(\Leftrightarrow-3x-6x+4x=-1-12-5\)

\(\Leftrightarrow-5x=-18\)

\(\Leftrightarrow x=\dfrac{18}{5}\)

\(\left(4\right)\) \(x\left(4x-3\right)-2x\left(2x-1\right)=5x-7\)

\(\Leftrightarrow4x^2-3x-4x^2+2x=5x-7\)

\(\Leftrightarrow-x-5x=-7\)

\(\Leftrightarrow-6x=-7\)

\(\Leftrightarrow x=\dfrac{7}{6}\)

\(\left(5\right)\) \(3x\left(2x-1\right)-6x\left(x+2\right)=-3x+4\)

\(\Leftrightarrow6x^2-3x-6x^2-12x=-3x+4\)

\(\Leftrightarrow-15x+3x=4\)

\(\Leftrightarrow-12x=4\)

\(\Leftrightarrow x=-\dfrac{1}{3}\)

Noob ơi, bạn phải đưa vào máy tính ý solve cái là ra x luôn, chỉ tội là đợi hơi lâu

a, 4.(18 - 5x) - 12(3x - 7) = 15(2x - 16) - 6(x + 14) 

=> 72 - 20x - 36x + 84 = 30x - 240 - 6x - 84

=> (72 + 84) + (-20x - 36x) = (30x - 6x) + (-240 - 84) 

=> 156 -  56x = 24x - 324 

=>  24x + 56x = 324 + 156 

=> 80x = 480 

=> x = 480 : 80 =  6 

Vậy x = 6 

\(2x+\frac{1}{2}=\frac{-5}{3}\)

\(2x=\frac{-5}{3}-\frac{1}{2}\)

\(2x=\frac{-10}{6}-\frac{3}{6}\)

\(2x=\frac{-13}{6}\)

\(x=\frac{-13}{6}:2\)

\(x=\frac{-13}{12}\)

a) \(\text{​​}/3x-5/-\frac{1}{7}=\frac{1}{3}\)                           b)\(\left(\frac{3}{5}x-\frac{2}{3}x-x\right).\frac{1}{7}=\frac{-5}{21}\)

  \(/3x-5/=\frac{10}{21}\)                                           \([x.\left(\frac{3}{5}-\frac{2}{3}-1\right)]=\frac{-5}{21}.7\)

 \(\Rightarrow3x-5=\frac{10}{21}hay3x-5=\frac{-10}{21}\)         \(\left[x.\frac{-16}{15}\right]=\frac{-5}{3}\)

\(3x=\frac{115}{21}\)                \(3x=\frac{95}{21}\)                         \(x=\frac{25}{16}\)

\(x=\frac{115}{63}\)                  \(x=\frac{95}{63}\)                             Vậy x = \(\frac{25}{16}\)

                      Vậy x \(\in\left\{\frac{115}{63};\frac{95}{63}\right\}\)

1, \(\left(x-4\right)^2-\left(2x+1\right)^2=\left(x-4-2x-1\right)\left(x-4+2x+1\right)=-3\left(x+5\right)\left(x-1\right).\)

\(\orbr{\begin{cases}x+5=0\\x-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-5\\x=1\end{cases}}}\)(mấy cái này áp dụng hàng đẳng thức lớp 8 mới hok)

2,\(x^3+x^2-4x-4=\left(x-2\right)\left(x^2+3x+2\right)=\left(x-2\right)\left(x+1\right)\left(x+2\right)\)

\(\orbr{\begin{cases}x=\mp2\\\end{cases}}x=-1\)

tương tụ lm tiếp nhe buồn ngủ quá rồi !

\(1,\frac{x+1}{x-2}=\frac{3}{4}\)

\(\Rightarrow3x-6=4x+4\)

\(\Rightarrow3x-4x=4+6\)

\(\Rightarrow-x=10\Leftrightarrow x=-10\)

\(2,\frac{x-1}{3}=\frac{x+3}{5}\)

\(\Rightarrow5x-5=3x+9\)

\(\Rightarrow5x-3x=9+5\)

\(\Rightarrow2x=14\Leftrightarrow x=7\)

\(3,\frac{2x+3}{24}=\frac{3x-1}{32}\)

\(\Rightarrow64x+96=72x-24\)

\(\Rightarrow72x-64x=24+96\)

\(\Rightarrow8x=120\)

\(\Rightarrow x=15\)

x/2 = 3/4

Căng, sự thật là nó rất căng

Nhg dù sao thì.....

1) \(A\left(x\right)=\left(x-4\right)^2-\left(2x+1\right)^2\)

Xét \(A\left(x\right)=0\)

\(\Rightarrow\left(x-4\right)^2-\left(2x+1\right)^2=0\)

\(\Rightarrow x^2-8x+16-4x^2-4x-1=0\)

\(\Rightarrow-3x^2-12x+15=0\)

\(\Rightarrow-3x^2+3x-15x+15=0\)

\(\Rightarrow-3x\left(x-1\right)-15\left(x-1\right)=0\)

\(\Rightarrow\left(x-1\right)\left(-3x-15\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x-1=0\\-3x-15=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=1\\x=-5\end{matrix}\right.\)

2)(Sửa đề nha, sai cmnr) \(B\left(x\right)=x^3+x^2-4x-4\)

Xét \(B\left(x\right)=0\)

\(\Rightarrow x^3+x^2-4x-4=0\)

\(\Rightarrow x^2\left(x+1\right)-4\left(x+1\right)=0\)

\(\Rightarrow\left(x^2-4\right)\left(x+1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x^2-4=0\\x+1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\pm2\\x=-1\end{matrix}\right.\)

Đó là những j mình biết