ααααEACBDF初二数学期末试题参考答案1-8ABCBCAAD9.答案不唯一10.相等的角是对顶角假11.-112.-1或213.3114.515.(2,1)16.917.(1,4)或(3,4)18.-819.-3<x≤7数轴略20.-11xx=0原式无意义21.(1)3(2)3.622.(1)960(2)b=160c=120d=6(3)17623.(1)甲、乙合做4天后(2)Cx=20A30万元B误工C28万元24.(1)k=2a=18(2)9192表格略(3)y=2x+4或y=2x+225.(1)340)100(34162)100(2xxxx三种方案38≤x≤40(2)a=293或298或30326.(1)y=x35(0<x<3)(2)825(3)①若∠EDF=∠ADE可证EF=EA=EC△CFE∽△CABBF=5-109=1041②若∠DEF=∠ADE可证四边形BFED、ADFE、DFCE为平行四边形BF=25③若∠DFE=∠ADE可证四边形DFCE为平行四边形△CFE∽△CAB竖式横式1386223961340603K3K5K5K5KαααααFEACBD35353kkk=3415BF=5-341253445