合并同类项1.合并同类项:(1)6a-9a(2)-5t+8t(3)-10x-(-9x)(4)-5m+(-7m)(5)-7y-6y(6)-3x-5x(7)5253432222xyyxxyyx(8)bababa2222132(9)322223babbaabbaa(10)13243222xxxxxx(11)-baba22212;(12)baba222(13)bababa2222132;(14)xxxx52731222(15)13243222xxxxxx(16)5x2y-y2-x-1+x2y+2x-9(17)4ab-7a2b2-8ab2+5a2b2-9ab+a2b2[来(18)22466284xxxx(19)222223337abababababab(20)-10x2+13x3-2+3x3-4x2-3+4x2(21)-35xy2+2x2y-29x2y-xy2-21x2y-xy2(22)2x2-xy-3y2+4xy+5+2y2-6x-32、先去括号,再合并同类项:(1)(2x-3y)+(5x+4y);(2)(8a-7b)-(4a-5b);(3)a-(2a+b)+2(a-2b);(4)3(5x+4)-(3x-5);(5)x+[x+(-2x-4y)];(6)(a+4b)-(3a-6b)(7)8x+2y+2(5x-2y)(8)(x2-y2)-4(2x2-3y2)(9)2x-(3x-2y+3)-(5y-2)(10)-(3a+2b)+(4a-3b+1)-(2a-b-3)3、合并同类项(1)4x+2y—5x—y(2)—3ab+7—2a2—9ab—3(3)x+[x+(-2x-4y)];(4)(a+4b)-(3a-6b)(5)3x2-1-2x-5+3x-x2(6)-0.8a2b-6ab-1.2a2b+5ab+a2b(7)222baba43ab21a32(8)6x2y+2xy-3x2y2-7x-5yx-4y2x2-6x2y(9)8x+2y+2(5x-2y)(10)3a-(4b-2a+1)(11)7m+3(m+2n)(12)(x2-y2)-4(2x2-3y2)(13)3x2-1-2x-5+3x-x2(14)4xy-3y2-3x2+xy-3xy-2x2-4y2(15)-0.8a2b-6ab-1.2a2b+5ab+a2b(15)222baba43ab21a32(16)5(a-b)2-7(a-b)+3(a-b)2-9(a-b)(17)3xn+1-4xn-1+12xn+1+32xn-1+5xn-2xn(18)3x2-1-2x-5+3x-x2(19)-0.8a2b-6ab-1.2a2b+5ab+a2b(20)222baba43ab21a32(21)6x2y+2xy-3x2y2-7x-5yx-4y2x2-6x2y(22)4x2y-8xy2+7-4x2y+12xy2-4;(23)a2-2ab+b2+2a2+2ab-b2.(24)3x2-1-2x-5+3x-x2(25)-0.8a2b-6ab-1.2a2b+5ab+a2b(26)222baba43ab21a32(27)6x2y+2xy-3x2y2-7x-5yx-4y2x2-6x2y(28)4x2y-8xy2+7-4x2y+12xy2-4;(29)a2-2ab+b2+2a2+2ab-b2.(30))32()54(722222abbaabbaba4.填空:(1)如果23kxyxy与是同类项,那么k.(2)如果3423xyabab与是同类项,那么x.y.(3)如果123237xyabab与是同类项,那么x.y.(4)如果232634kxyxy与是同类项,那么k.(5)如果kyx23与2x是同类项,那么k.