a,5x+2-12x-4=2x+8
<=>-7x-2x=8+2
<=>-9x=10
<=>x=\(\dfrac{-10}{9}\)
b,(x-2)(3x-2)+(3x-2)(3x+2)=0
<=>(3x-2)(x-2+3x+2)=0
<=>(3x-2)4x=0
<=>x=\(\dfrac{2}{3}\) ,x=0
c,đk x khác -1,1.
=>(4x+5)(x+1)+(2x-1)(x-1)=6(x-1)(x+1)
<=>4x\(^2\)+9x+5+2x\(^2\) -3x+1=6x\(^{^{ }2}\)-6
<=>6x\(^2\)+6x+6-6x\(^2\) +6=0
<=>6x+12=0
<=.x=-2





giải thích giùm mình với