1.8或4(B^2-4AC=0),2.2个不相同的根,(B^2-4AC大于0)3.X^2+2X=0 或 X^2-2X=0
4.2*160X+2*100X=160*100 5.25 6.3 4 5
7.6 8.原来有8个人,设原来有X个人,120/X-3=3X/2
1.8或4(B^2-4AC=0),2.2个不相同的根,(B^2-4AC大于0)3.X^2+2X=0 或 X^2-2X=0
4.2*160X+2*100X=160*100 5.25 6.3 4 5
7.6 8.原来有8个人,设原来有X个人,120/X-3=3X/2