1、 2015 西城区初二（上）期末数学 30 3 1 3 2 2 A B C 4 D 4 2 3 A B C D 3 3 A xz+yz= z x+y B 3a 2 b 2ab 2 +ab=ab 3a 2b C 6xy 2 8y 3 =2y 2 3x 4y D x 2 +3x 4= x+2 x 2 +3x 4 3 A B C D 5 3 y= m 2 x+3 m A m 0 B m 0 C m 2 D m 2 6 3 A B C D 7 3 2 4 A 8 B 10 C 8 10 D 6 12 8 3 B D E C ABD ACE AEC=105 DAE A 30 B 40 C 50 D 65
2、 9 3 ABC BD ABC AC D DE AB E BC=5 BCD 5 ED A B 1 C 2 D 5 10 3 y= x+m y=nx+5n n 0 2 x x+m nx+5n 0 A 5 4 3 B 4 3 C 4 3 2 D 3 2 20 11 14 3 15 18 3 11 3 x 12 3 x 2 4y 2 = 13 3 P 2 3 y 14 3 B AD ABC= D AB=ED ABC EDB 15 2 ABC ABC= ACB AB AC M AB N MB AB=8 MBC 14 BC 16 2 y= 2x+1 2 x 3 y 17 2 AB AB MN MN C
3、D BC=CD MN DE E A C DE AB 18 2 1500m 4min t min y m y t 30m/min 500m 480m 30min 50 19 20 6 21 25 6 26 6 27 7 19 6 1 a b 2 +3 a b 2 2ax 2 12ax+18a 20 6 1 2 21 5 a b=2 22 5 +1= 23 5 A O B A= C 1= 2 OD=OB AD=CB 24 5 “ ” 1352km 52km 8h 2.5 25 5 xOy y= 2x y 4 y B x C 1 y= 2x BC 2 C y= 2x P m 2 m CP 26 6
4、ax 2 +bx+c a 0 a x+m 2 +n ax 2 +bx+c x 2 +11x+24= +24 = = = x+8 x+3 1 x 2 +8x 1 x+m 2 +n 2 x 2 3x 40 “” 3 x y x 2 +y 2 2x 4y+16 27 7 ABC 1 1 D AB E AC BD=CE BE CD F BF CF 2 D AB E AC BD=CE BE CD F BFD FBD 6 28 6 1 = 2 = 14 7 29 7 8.1 9 = 8.1 9 4 2=4 2 1 2 4= 4 3 = 4 x y x 0 x 1 x y x y x 1 x y “ ” “
5、 ” 30 7 1 xOy A y B AB y AB=OA C OA BC BD BC x D 1 1 2 OA AC OD CD CBD CD H AH BAH 参考答案与试题解析 30 3 1 2 2 = = A 2 A B C D D 3 A xz+yz= z x y A B 3a 2 b 2ab 2 +ab=ab 3a 2b+1 B C C D D C 4 A B C D D 5 y= m 2 x+3 m 2 0 m 2 C 6 = D 7 2 4 2 4 4 10 2 2 4 2+2=4 10 B 8 ABD ACE ADB= AEC=105 ADE= AED=75 DAE=180
6、 75 75 =30 A 9 DF BC BC F BC=5 BCD 5 DF=2 BD ABC DE AB DF BC DE=DF=2 C 10 y= x+m y=nx+5n n 0 2 x x+m nx+5n x 2 y=nx+5n=0 x= 5 nx+5n 0 x 5 x+m nx+5n 0 5 x 2 x x+m nx+5n 0 3 4 B 20 11 14 3 15 18 3 11 x 1 0 x 1 x 1 12 x 2 4y 2 = x+2y x 2y x+2y x 2y 13 P 2 3 y 2 3 2 3 14 BC=DB ABC EDB ABC EDB SAS BC=DB
7、15 MN AB AM=BM MBC =BM+CM+BC=AM+CM+BC=AC+BC AB=8 MBC 14 BC=14 8=6 6 16 x= 2 y= 2x+1=5 x=3 y= 2x+1= 5 y 5 y 5 5 y 5 17 AB MN DE MN ABC= EDC=90 ABC EDC ABC EDC ASA DE=AB ASA 18 4min 0 t 4 t=4 y=120 30m/min 4 t 10 t=10 y=0 10 30=300 m 300 10 4 =50m/min 10 t a y a= t=34 34 30=1020 1500 y=1500 1020=480 1
8、500 30=50 min 50 19 20 6 21 25 6 26 6 27 7 19 1 a b 2 +3 a b = a b a b+3 2 2ax 2 12ax+18a=2a x 2 6x+9 =2a x 3 2 20 1 = = 2 = = = 21 = = = a b=2 = 22 x 2 1 x 2 4x+x 2 1=2x x 1 2x 2 4x 1=2x 2 2x 2x=1 x= x= x= 23 1= 2 1+ COD= 2+ COD AOD= COB AOD COB AOD COB AAS AD=CB 24 xkm/h 2.5xkm/h =8 x=104 x=104 2.
9、5x=260 260km/h 25 1 BC y= 2x+4 2 y= 2x P m 2 2= 2m m= 1 P 1 2 BC x C C 2 0 PC y=kx+b CP y= x+ 26 1 x 2 +8x 1=x 2 +8x+4 2 4 2 1= x+4 2 17 2 x 2 3x 40=x 2 3x+ 2 2 40 = x 2 = x + x = x+5 x 8 3 x 2 +y 2 2x 4y+16= x 2 2x+1 + y 2 4y+4 +11= x 1 2 + y 2 2 +11 11 x y x 2 +y 2 2x 4y+16 27 1 BF=CF ABC ABC= ACB
10、=60 BCD CBE BCD CBE SAS BCD= CBE BF=CF 2 1 BCD= CBE ACB=60 BCD= CBE=x DBF=60 x BFD FD=FB FBD= FDB A FBD= FDB 60 FBDxy ABC FBD 60 FD=FB DB=DF FBD= BFD=2x 60 x=2x x=20 FBD=40 BD=BF BDF= BFD=2x BDF DBF+ BDF+ BFD=180 60 x+2x+2x=180 x=40 FBD=20 FBD 40 20 6 28 1 =2 1+3 =2 = 2 =5 =5 a b= 5ab = = = 1 2 14 7 29 1 2 x x 4= 3 3= 3 4 1 x y=x y x y=x y x y=x y y 2 xy+x=0 x x 4 0 x 0 x 4 y= x 4 y y min = =2 =4 2 30 1 1 2 OA+AC=OD B BE x E AOEB BE=AO ABE=90 AB=AO AB=BE BD BC CBD=90 ABC= DBE ABC BDE ABC BDE AC=DE OE=AB=OA AO+AC=OD 2 1 ABC BDE BC=BD BD BC BCD BCD=45 BH CBD BHC=90 BAO=90 A C H B BAH= BCH=45
