(4)、6,7,8,9
3024=2*3*2*3*2*3*2*3*2*7
=(2*3)*7*(2*2*2)*(3*3)
(100-90)*2/(90-86)=5
5*5*3.6/(5*4.5)=4
(180/2)/(70-50)=4.5
30*(a+1)=40*(a-2)
a=11
(4)、6,7,8,9
3024=2*3*2*3*2*3*2*3*2*7
=(2*3)*7*(2*2*2)*(3*3)
(100-90)*2/(90-86)=5
5*5*3.6/(5*4.5)=4
(180/2)/(70-50)=4.5
30*(a+1)=40*(a-2)
a=11