10.3-10.4 习题课-2021-2022学年八年级下册数学【拉网提优大小卷】苏科版

.EF=BE+DE 10.3习题课(1) 3 1B2.C3B4B5.C67.8.6 9.号10. -2 a2b-a 1山.(1)原式=b6=, (2)原式=x千y)(x-y y(x-y) (2)如图，由(1)知，△ADE≌△ABE(SAS), (x+y)(x-y) ∴.AE=AE,∠DAE=BAE, xy-y-zy 3y2 设BE=x,DF=y, (x+y)(x-y)2之； .正方形ABCD的边长为1， (3)原式= 2p-3g+2p+3g 4p .CE=1-x,CF=1-y. 2p+3q)(2p-3q)4p-9g △CEF的周长为2， ∴.CE+CF+EF=2, (4)原式=a一_a2-11 a-1a-1a-i' .1-x+1-y+EF=2, 2 2(y-1) ..EF=x+y=BE+DF=DE'+DF=E'F. (5)原式=y+1)y-D(+DyD (AE=AE, y+1 -3y+3 3 在△E'AF和△EAF中，EF=EF, (y+1)(y-1)(y+1)(y-1)y+1 AF-AF, (6)原式=二2十+2 2x-2 .∴.△EAF≌△EAF(SSS), x(x-1) x(x-1) x(x-1) ∴.∠EAF=/EAF, x-2+x2+x-2x+2= ∴.∠DAE+∠DAF=∠BAE+∠DAF=∠EAF. ∠DAF+ZEAF+∠BAE-90°， x(x-1) x(-D-x-I 12.(1)② ./EAF=45°. (2)丢掉了分母 第10章分式 (3)原式= x-4 2(x-2) 10.1~10.2习题课 (.x+2)(x-2) -(x+2)(x-2) x-4-2.x+4 1.C2.A3.A4.A5.B6.D7.28.6.x2y2 (x+2)(x-2) (x+2)(x-2) 义专m器总 11.-1或-312.18 13.4)原式=+2)3=1- x+2 x+2 1B.1:分式2当没意义， (2)原式=2x-2+1_2(x+1)(x-1)+1=2(x+1)+ x-1 .x-1=0,解得x=1. x-1 1 （2:分式有意文， x-1 分式的值为整数，且x为整数， ∴.x一1≠0，即x≠1. .x一1=士1， (3):分式的值为0， x=2或0. 240解得x=-2. 10.3习题课(2) x1≠0， 1.原式=15-4-15=-1 H原式-a) 5a 5a 2.原式=c。+0+4,+4_20十0=2a: 把a=2,b=- 代入，原式 2+2×(-2)1 a十2 a十2 a十2 2a 1 2-2×(-2)3 3.原式=a+2a-2)-a+2=(a+2a-2 a-2 a+2 1 15.(1)工=h,y=a (a+2)(a-2)(a+2)(a-2)a-2 ac abe'be abci 2(x-1) x+5 3.x+3 2)2兰)20+， 4.x 4.原式= (x+1)(x-1)F(x+1)(x-1)-(x+1)(x-1) 3 x(x-3) x-1 2.x+6-2(x+3)(x-3) y(y一x) 4(m十+3) （3)m3-2(n十3)(m, x2-y2 x2-y2 y m-3 x十y 2(m+3)2(m+3)(m-3) 1 =x-1-x2+1 16.ab=1,bc1 ac 1 x(x一1) a+b3'b+c4'a+c=5’ -x(x-1) 0+=3,+-=4,+-5 x(x-1) =-1； 上述三式相加可得2+2+2=12， 7原式=-义 2x=1; at b c y-x y-xy-x .1++1=6, 8.原式= 2(.x+3) 12 2(x+3)(x-3) 2(x+3)(x-3) (x-1)(x-3)-x2+6x-9 (x-3)2 bcactab-6. 2(x+3)(.x-3)=2(x+3)(x-3)=-2(x+3)(x-3)= abc x-3 abc 一2(x+3) (.x-1)2 1x一11 9,原武(x十)-D十x市一++中中 97 10.原式=a+2g-2)-4-2=4-2-a-2=-4 a+2 山原式兴，兴，-5： 10.4习题课(1) (2)原式= 6 a-3 1.原式=a十2)2 ,a2_a(a+2)_a2+2a (a+3)(a-3) +(a+3)(a-3) a(a-1)a+2a-1 a-1 a+3 2.原式=2g.15c2二5a (a+3)(a-3)a-3: 3c3·6a'8-3c9 3.原式=4a+).15a2b (3)原式-·品-品 _12a 5ab (a+b)(a-b)a-bi (4)原式=x2)(x+22.(x士2-2-2y (.x+y)2 x+2y x十y ￥原式=a·a)1D-a十号： a(a-1)a-1 2照式=a·号+克中十 1 1 5原式=Q-1÷+a-2 (a+1)(a-1) a x