1 15-1 15-2 . . . . . .1234563 54. 1. 2. 3. 1. 2. 3. .1 2. 3. .1. 2. .6 . .: : . . . .: : . . . .: : . .am an = am+n（am） = amnn (ab)n = an bn a b . 71. 2. 3. . . . . 81. ()( )( ) .9: .1-10 :2aa1b3) 3()2(-2-11=m(a+b+c)= mambmc+2a2(3a2-5b)=2a2.3a22a2.(-5b)+=6a4-10a2b(-2a2)(3ab2-5b)=(-2a2).3ab2(-2a2).(-5b)+=-6a3b2+10a2b:2. mcmbma+)(cbam+12 - .13(a+b)(m+n)=am+an+bm+bn - .3. 14 (x+2)(x3) =: . .: .15 (a+b)(a-b) = a-b .1. abab a b : . : . : .bba-b(a+b)(a-b) ( :a+b)(a-b) =a-b17 : : . a b .(a+b)(a-b) = a-b18 1. : (1) (3x+2)(3x-2) (2) (b+2a)(2a-b) (3)(-x+2y)(-x-2y) (1) (3x+2)(3x-2) =(3x)2-22=9x2-4(2) (b+2a)(2a-b)=(2a)2-b2=(2a+b)(2a-b)=4a2-b2(3) (-x+2y)(-x-2y)=(-x)2-(2y)2=x2-4y2:(a+b)2=a2+2ab+b2(a-b)2=a2-2ab+b2 : )( = 2 .2. 20baab1234 . : : : 2- 3- .4- b .:2113 aabb a 1- :2 2- 3- : 2- 3- :4- 2- 3- .422 :4. a b .(a+b)2= a2 +2ab+b2(a-b)2= a2 - 2ab+b21. 2- 2. 3. 2 23:1. (3x+4y )22. (3x-4y )23. (-3x+4y )24. (-3x-4y )2= 9x2-24xy+16y2= 9x2+24xy+16y2= 9x2-24xy+16y2= 9x2+24xy+16y2(a+b)2=(-a-b)2(a-b)2=(-a+b)2241-10: m=4 10n=5 10. 3m+2n . : .:252-. :(1)(-4x)(2x2+3x-1)； 解：解： (-4x)(2x2+3x-1)-8x3-12x2+4x1-: 1 .(-4(-4x x)(2)(2x x2 2) )(-4(-4x x)3)3x x(-4(-4x x)(-1)(-1)+ + + + + + +:26-2a2(ab+b2)-5a(a2b-ab2) 解解:原式原式-2a3b-2a2b2-5a3b+5a2b2-2a3b-2a2b2-5a3b+5a2b21. : 2. .-7a3b+3a2b2 3-. : 27 (-2ab)3(5a2b2b3) =(-8a3b3)(5a2b2b3) =(-8a3b3)(5a2b)+(-8a3b3)(-2b3） =-40a5b4+16a3b6: .4-. :28 (a+3b-2c)(a-3b-2c)= (a-2c)+3b (a-2c)-3b= (a-2c)2-(3b)2= a2-4ac+4c2-9b24-. : .29 (1)(2)(3)(4)(5)(a+b+c)(a+b-c) =(a+b)+c(a+b)-c =(a+b)2-c2 ( ) =a2+2ab+b2-c2 ( ) . . .1. 2. 3. . - . . 2 ) ). - .(6) (2x-3)(x+1) =2x2-x-3 （ ） - . A: 312. : (1)19982002: (1)= (2000+2)(2000-2)= 20002-22= 4000000-4= 3999996(2)= 32(1) (x3+mx+n)(x2-5x+3) x2 x3 m n .(2) 2x2+4x-5 a(x+k)2+m .(3) (ax+b)(3x+2)=6x2+kx-1 a b k .(4) a+b=9 ab=14 a2+b2 . ! x2 :nx2-5mx2=(n-5m)x2 x3 :3x3+mx3=(3+m)x3 x2 :n-5m=0 3+m=0 m= -3 n= -15a(x+k)2+m=a(x2+2kx+k2)+m =ax2+2akx+ak2+m=2x2+4x-5 a=2 a=2 2ak=4 k=1 ak2+m=-5 m= -82x2+4x-5 =2(x+1)2-8(ax+b)(3x+2)=3ax2+(2a+3b)x+2b =6x2+kx-1 3a=6 a=2 2a+3b=k b= -0.5 2b= -1 k=0.5 :a2+b2=(a+b)2-2ab=92-214=5333