Mik làm chừng này thôi nha
`a)2x+1=15-5x`
`=>2x+5x=15-1`
`=>7x=14`
`=>x=2`
`b)3x-2=2x+5`
`=>3x-2x=5+2`
`=>x=7`
`c)7(x-2)=5(3x+1)`
`=>7x-14=15x+5`
`=>7x-15x=5+14`
`=>-8x=19`
`=>x=19/-8`
`d)2x+5=20-3x`
`=>2x+3x=20-5`
`=>5x=15`
`=>x=3`
`e)-4x+8=0`
`=>-4x=-8`
`=>x=2`
`f)x-3=18-5x`
`=>x+5x=18+3`
`=>6x=21`
`=>x=21/6`
`g)x(2x-1)=0`
⇒\(\left[ \begin{array}{l}x=0\\2x-1=0\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=0\\x=\frac{1}{2}\end{array} \right.\)
`h)3x-1=x+3`
`=>3x-x=3+1`
`=>2x=4`
`=>x=2`
`j)2(x+1)=5x-7`
`=>2x+2=5x-7`
`=>2x-5x=-7-2`
`=>-3x=-9`
`=>x=3`
`k)2x+6=0`
`=>2(x+6)=0`
`=>x+6=0`
`=>x=-6`
`m)2x-3=0`
`=>2x=3`
`=>x=3/2`
`n)4x+20=0`
`=>4(x+5)=0`
`=>x+5=0`
`=>x=-5`
$@FBoy24$
