Bài 1:a) 2x+6=0 <=>2x=-6 <=>x=-3b)4x+20=0 <=>4x=-20 <=>x=-5c)2(x+1)=5x-7 <=>2x+2=5x-7 <=>2x-5x=-7+2 <=>-3x=-5 <=>x=5/3d)2x-3=0 <=>2x=3 <=>x=3/2e)3x-1=x+3 <=>3x-x=3+1 <=>2x=4 <=>x=2f)15-7x=9-3x<=>15-9=-3x+7x<=>6x=4<=>x=2/3g)x-3=18<=>x=21 h)2x+1=15-5x<=>2x+5x=15-1<=>7x=14<=>x=2i)3x-2=2x+5<=>3x-2x=5+2<=>x=7k)-4x+8=0<=>-4x=-8<=>x=2m)4x+5=3x<=>x=-5