Math topic中文Combining like termsSimplifying expressions by combining (collecting) like terms, including recognising which terms are likePractice questions1若3xm+5y23x^{m+5}y^{2}3xm+5y2与x3ynx^{3}y^{n}x3yn的和是单项式，则mn=m^{n}=mn= ___ ．2若2x3y22x^{3}y^{2}2x3y2和−ynx3m-y^{n}x^{3m}−ynx3m是同类项，则(m−n)2018=(m-n)^{2018}=(m−n)2018=___.3若单项式2x2ya+b2x^{2}y^{a+b}2x2ya+b与−13xa−by4- \dfrac {1}{3}x^{a-b}y^{4}−31xa−by4是同类项，则aaa，bbb的值分别为()()() A. a=3a=3a=3，b=1b=1b=1 B. a=−3a=-3a=−3，b=1b=1b=1…4若−3xy2m-3xy^{2m}−3xy2m与5x2n−3y85x^{2n-3}y^{8}5x2n−3y8是同类项，则mmm、nnn的值分别是()(\quad)() A. m=4m=4m=4，n=2n=2n=2 B. m=4m=4m=4，n=1n=1n=1 C. m=2m=2m=2，n=2n=2n=2…5下列各组中，是同类项的是()(\quad)() A. −2x2y-2x^{2}y−2x2y和xy2xy^{2}xy2 B. x2yx^{2}yx2y和x2zx^{2}zx2z C. 2mn2mn2mn和4nm4nm4nm D. −ab-ab−ab和abcabcabc6下面是小丽同学做的合并同类项的题，其中正确的是()()() A. 2a+3b=6ab2a+3b=6ab2a+3b=6ab B. ab−ba=0ab-ba=0ab−ba=0 C. 5a3−4a3=15a^{3}-4a^{3}=15a3−4a3=1 D. −a−a=0-a-a=0−a−a=07化简下列各题： (1)3x−4x2+7−3x+2x2+1(2)2(5a2−2a)−4(−3a+2a2)(1)3x-4{{x}^{2}}+7-3x+2{{x}^{2}}+1(2)2(5{{a}^{2}}-2a)-4(-3a+2{{a}^{2}})(1)3x−4x2+7−3x+2x2+1(2)2(5a2−2a)−4(−3a+2a2)8下列为同类项的一组是()(\quad)() A. ababab与7a7a7a B. −xy2-xy^{2}−xy2与14yx\dfrac{1}{4}yx41yx C. xxx与222 D. 777与−13-\dfrac{1}{3}−319若−3x2my3-3x^{2m}y^{3}−3x2my3与2x4yn2x^{4}y^{n}2x4yn是同类项，那么m−n=()m-n=(\quad)m−n=() A. 000 B. 111 C. −1-1−1 D. −5-5−510如果单项式xa+1y3x^{a+1}y^{3}xa+1y3与2x3yb2x^{3}y^{b}2x3yb是同类项，那么ab=a^{b}=ab= ___ ．11下列运算结果中正确的是()(\quad)() A. a2⋅a3=a6a^{2}\boldsymbol{⋅}a^{3}=a^{6}a2⋅a3=a6 B. (a3)3=a6(a^{3})^{3}=a^{6}(a3)3=a6 C. (−2a)3=−2a3(-2a)^{3}=-2a^{3}(−2a)3=−2a3 D. a2+a2=2a2a^{2}+a^{2}=2a^{2}a2+a2=2a2…12若代数式3a5bm3a^{5}b^{m}3a5bm与−2anb2-2a^{n}b^{2}−2anb2是同类项，那么m=m=m= ___ ，n=n=n= ___ ．