八年级上寒假作业答案.doc

by _2013() 1. 123819884562. 3. 124.12345.12346.7.8.9. 1231. b.c.2. 3. 4. 5. d6. 7. 8. (1)29. 1210. 11. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 1. 122. 123. 4. 5. 6. 7. 8. 9. 10. 11. c12. ,1. 1 2 2. 123. 124. 5. 6. 7. 12348. 1d2b3a9. 1d2c10. 11. 12. ,13. ) 14. 15. 16.1 2 317.1b2c3a18. 19.20.21.22.12323.1.d 2.a 3.d 4.a 5.d 6.c 7.b 8.d 9.c 10.d11.80 12.75 13.6 4 14.8015.(n-2)180=2520n=16 16+1=1716. bccdb=180-dcb-dbc dcb+dbc=180-a+acd+abdcdb=180-180-a+acd+abd 3a=a+40+20 a=3017. c+dac=adb b=dac c+b=adbb+c+bac=180 adc=bac18. abd=(1/2)bd*ae acd=(1/2)dc*ae adabc,bd=abd=ab+bd+ad=ab+(1/2)bc+ad acd=ac+ad+dc=ac+ad+(1/2)bcab-ac=2cm (3)bc=7,bd=1/2bc=3.5abd=bdae=5.251.d 2.a 3.c 4.b 5.c 6.d 7.a 8.c 9.c 10.b 11.b 12.b13.b=e 14.35 15.bc=fe 16.ab=de17.adadbcdac=bcaabccdadac=bcaad=dab=dabccdaab=cd19. 1cdabbeac12ab=acab0acoao=ao1=2ab=ac aboacoob=oc2 cdabbeacbdo=ceo=90bdoceobdo=ceobod=coeob=ocbdoceoaasod=oeodaboeacoa=oartaodrtaoe1=220. dab=eacdac=eabadcaebab=acdac=eabad=aeadcaebb=cab=ac,manamcanbam=an21. ab=ac, ab=acad=aeb=cade=aedabeadcb=cad=aeade=aedabcacd22. c=doc=odboc=doeboceodbc=de,abofdoac=df ab=ef23. (1.d 2.a 3.d 4.d 5.c 6.c 7.b 8.a 9.c 10.a11.810076 12.55 13.30 14. 1815.abaca100abc40abdcbd1/2abc20bdcaabd10020120bdbebdebedbdc20bde80cdebdcbde120804024. afe=dfc=90-fdcde=befdc=ebcafe=90-ebc=aae=fe eaf25. poap1pobp2,pm=p1mpn=p2npmn=pm+pn+mn=mn+p1m+p2n=p1p2=5cm1.c 2.d 3.b 4.b 5.d 6.d 7.c 8.b 9.b 10.a11.1 12.4 13.0 14.(a+1)215.1=3b5+7b5=10b5(2)=m(-2mn3)= -2m2n33=-2x2+3x-6-(x3-2x2-2x=5x-64=(x-y)2*(x+y)(x-y)+(x+y)2*(x+y)(x-y)=2(x2-y2)=2x2-2y226. 1=3mn2m2-2mn+n2)=3mn2(m-n)2(2)=y3(y2-1)=y3(y+1)(y-1)(3)=2*b2-2*7b+2*12=2(b2-7b+12)27. 4a2+9b2)(2a+3b)(2a-3b)=(4a2+9b2)(4a2-9b2)=16a4-81b4 28. (1)=m-m2+m2-12=m-1m=-3=-3-1=-42=-3x3+6x2y-(-3x3-4x2y)=10x2yx=-1,y=-2=108-1)2*(-2)=-2029. a2-4b3=21 (+2b)(a-2b)=21 a+2b=-3 a-2b=21a+2b)=21-3=-7 a+2b=-3a-2b=-7 a=-5 b=11.b 2.d 3.a 4.b 5.a 6.b 7.a 8.a 9.d 10.d11. 5 12. 3 13. 8*10-6 14.3*1/12+1/x+3*1/x=115.1=x-1/x * 1/x - x-1/x*x=x2-2/x2(2)=x2y3*x4 1/y6=x6/y230. (1)x-1)(x+1 x+1+2x(x-1)=2(