點P與Q在線段AB上,AP:PB=2:3,AQ:QB=3:4,且PQ=3,求AB的長.

點P與Q在線段AB上,AP:PB=2:3,AQ:QB=3:4,且PQ=3,求AB的長.

設AP=2a,PB=3a,AQ=3b,QB=4b,
AQ-AP=PQ:3b-2a=3
2a+3a=3b+4b
兩方程可以就出
a=21,b=15
AB=5a=105