a: =>5-2x-6=8-3x+15
=>-2x-1=-3x+23
=>-2x+3x=23+1
=>x=24
b: =>(x-3)(-x-2)-(x-3)(x2-2)=0
\(\Leftrightarrow\left(x-3\right)\left(-x-2-x^2+2\right)=0\)
\(\Leftrightarrow x\left(x+1\right)\left(x-3\right)=0\)
hay \(x\in\left\{0;-1;3\right\}\)
c: \(\Rightarrow5x^2-8x+5x-8=0\)
=>(5x-8)(x+1)=0
=>x=8/5 hoặc x=-1
d: \(\Leftrightarrow6\left(2x-5\right)-8\left(3x-2\right)=3\left(5x-1\right)\)
\(\Leftrightarrow12x-30-24x+16-15x+3=0\)
\(\Leftrightarrow-27x-11=0\)
hay x=-11/27
e: \(\Leftrightarrow x^2+2x+1-4x+4=-2x+2x^2+4\)
\(\Leftrightarrow2x^2-2x+4-x^2+2x-5=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=1\left(loại\right)\\x=-1\left(loại\right)\end{matrix}\right.\)
