a,7x+21=0 b,5x-2=0c,-2x+28=0 c,-2x+28=0
d,0,25x+1.5=0 e,6-3x=0 f,2x+3x-20=0
g,12x-24=8x h,x-5=3-x k,15-8x=9-5x
l,3x+1=7x-11 m,2x+3=x+5 n,4x-3=2x+9
o,2x-(3-5x)=4(x+9) p,10x-3-5x=3x+12 q,3x-(x+2)=5(x+5)-(x-5)
r,2(x-3)+5x(x-1)=5x^2 s,2x+6+x=3(x+2) chú ý ss,2x+6+x=3(x+10) chú ý
y,-6(1,5-2x)=3(-15-2x) t,0,1-2(0,5y-0,1)=2(t-2,5)
z,(x-2)(x+7)=0 chú ý sang dạng cách giải dạng phương trình tiếp theo