cau 1
(3x-1)(2x-3)(2x-3)(x+5)=0
\(\Leftrightarrow\)(2x-3)[(3x-1)*(x+5)]=0
\(\Leftrightarrow\)(2x-3)(3x2+15x-x-5)=0
\(\Leftrightarrow\)(2x-3)[3x(x+5)-(x+5)]=0
\(\Leftrightarrow\)(2x-3)(x+5)(3x-1)=0
\(\Leftrightarrow\)2x-3=0 hoac x+5=0 hoac 3x-1=0
\(\Leftrightarrow\)x=3/2\(\Leftrightarrow\)x=-5\(\Leftrightarrow\)x=1/3
vay s={3/2,-5,1/3}
cau 2
(x+1)(x+4)=(2-x)(x+2)
\(\Leftrightarrow\)x2+4x+x+4=4-x2
\(\Leftrightarrow\)x2+4x+x+4-4+x2=0
\(\Leftrightarrow\)2x2+5x=0
\(\Leftrightarrow\)x(2x+5)=0
\(\Leftrightarrow\)x=0 hoac 2x+5=0
\(\Leftrightarrow\)x=0\(\Leftrightarrow\)x=-5/2
vay s={0,-5/2}