1: \(\Leftrightarrow\dfrac{4x+6-3}{4x-6}=\dfrac{2}{5}\)
=>\(\dfrac{4x+3}{4x-6}=\dfrac{2}{5}\)
=>20x+15=8x-12
=>12x=-27
=>x=-9/4
2: \(\Leftrightarrow x^2+3x+2-5x+10=12+x^2-4\)
=>-2x+12=8
=>-2x=-4
=>x=2(loại)
3: \(\Leftrightarrow x-2-7x+7=-1\)
=>-6x+5=-1
=>-6x=-6
=>x=1(loại)
4: \(\Leftrightarrow3x-3+9=x+2\)
=>3x+6=x+2
=>x=-2(loại)