
2024-2025學(xué)年北師大版七年級(jí)數(shù)學(xué)下冊(cè)《第1章整式的乘除》 單元基礎(chǔ)達(dá)標(biāo)測(cè)試題(附答案) 一、單選題 1.一張A4紙的規(guī)格為210×297mm,它的面積約為0.00000006237平方千米.將數(shù)字0.00000006237用科學(xué)記數(shù)法表示應(yīng)為(????) A.0.6237×10?7 B.6.237×10?8 C.62.37×10?6 D.6.237×10?7 2.計(jì)算:?21a2b3c÷3ab=(????) A.?7ab2 B.?7ab2c C.7ab2c D.?7abc 3.下列各式中能用平方差公式計(jì)算的是(????) A.3a+2b2b?3a B.2?3x3x?2 C.m+3nn?3m D.4x?y?4x+y 4.若am=3,an=2,則am?n的值是( ?。?A.1.5 B.6 C.9 D.8 5.已知▲?(?2xy)=4x2y?6xy2,則▲表示的式子為(???) A.?2x+3y B.2x+3y C.?2x?3y D.2x?3y 6.下列運(yùn)算正確的是(???) A.(?2ac)?(?3ab)3=?54a4b3c B.5x2y2?3x32=15x12y2 C.(?0.1ab)??10b23=?ab7 D.2×10n×12×10n=102n 7.?0.252023×42023等于(????) A.1 B.?1 C.2023 D.?2023 8.已知a=?3?2,b=?13?2,c=?13?0,則a、b、c的大小關(guān)系是(????) A.a(chǎn)>b>c B.a(chǎn)>c>b C.c>b>a D.b>c>a 9.若多項(xiàng)式x2+mx?15=(x+3)(x?5),則m的值為(??) A.8 B.?8 C.2 D.?2 10.已知x2+y2=4,xy=2,則x+y2的值為(????) A.8 B.10 C.12 D.14 二、填空題 11.一種細(xì)胞的直徑為2×10?3厘米,將2×10?3寫成小數(shù)為 . 12.計(jì)算?x23的結(jié)果是 . 13.已知多項(xiàng)式x2+mx+4是完全平方式,則m的值為 . 14.計(jì)算:?3m+2n3m+2n= . 15.?12m+12= . 16.若a2?a?3=0,則3?a2+a的值為 . 17.計(jì)算:2x23?x3??2x33+4x2?x7= . 18.若a+2b=2,則3a?9b的值為 . 19.若10m=20,10n=5,則m+n?1= . 20.如果代數(shù)式x?3x+1的值等于1,那么x的值為 . 三、解答題 21.(1)已知2x+3y=4,求4x?8y的值; (2)已知9b=6,3a=2,求33a+2b的值. 22.(推理能力)閱讀下面例題的解題過(guò)程: 例:已知x2=m,x3=n,請(qǐng)你用含m,n的代數(shù)式表示x11. 解:因?yàn)閤2=m,x3=n,所以x11=x2·x33=mn3,或x11=x24?x3=m4n. 解決問(wèn)題:若a=45,b=54,試用含a,b的代數(shù)式表示2020. 23.計(jì)算:(2x?y)2?(x?2y)2. 24.計(jì)算下列各式: (1)3x?2y6x?4y; (2)a+b3a?2b?ba?b; (3)y+2y?2?y?1y+5; (4)a?ba2+ab+b2. 25.計(jì)算: (1)2a+3b2?3a+2b2b?3a; (2)x?yx2+xy+y2?2yx2?12y2÷2x2. 26.先化簡(jiǎn),再求值:2x+3y2?2x+y2x?y?2y5y+3x,其中x=13,y=?12. 27.先化簡(jiǎn),再求值:x?y2+x+yx?y÷2x,其中x=2023,y=2024. 28.已知m滿足3m?20252+2024?3m2=5,求2025?3m2024?3m的值. 29.?dāng)?shù)學(xué)中的許多規(guī)律不僅可以通過(guò)數(shù)的運(yùn)算發(fā)現(xiàn),也可以通過(guò)圖形的面積發(fā)現(xiàn) (1)如圖①,在邊長(zhǎng)為a的正方形紙片上剪去一個(gè)邊長(zhǎng)為bbc>a, 故選;D. 9.解:∵(x+3)(x?5)=x2?5x+3x?15=x2?2x?15=x2+mx?15, ∴m=?2, 故選:D. 10.解:∵x2+y2=4,xy=2, ∴x+y2=x2+y2+2xy=4+2×2=8, 故選:A. 11.解:2×10?3=0.002, 故答案為:0.002. 12.解:?x23=?13?x23=?x6. 故答案為:?x6. 13.解:∵x2+mx+4=x2+mx+±22, ∴+mx=±2?x?±2, ∴m=±4, 故答案為:±4. 14.解:?3m+2n3m+2n=2n2?3m2=4n2?9m2. 故答案為:4n2?9m2 15.解:?12m+12=14m2?m+1, 故答案為:14m2?m+1. 16.解:∵ a2?a?3=0, ∴ a2?a=3, ∴ 3?a2+a=6+3a?2a?a2=?a2+a+6=?(a2?a)+6, ∵ a2?a=3, ∴原式=?3+6=3. 故答案為:3. 17.解:2x23?x3??2x33+4x2?x7, =2x6·x3+8x9+4x9, =2x9+8x9+4x9, =14x9. 18.解:當(dāng)a+2b=2時(shí), 3a?9b=3a?32b=3a+2b=32=9; 故答案為:9. 19.解:∵10m=20,10n=5, ∴10m+n?1=10m×10n÷10=20×5÷10=10, ∴m+n?1=1 故答案為:1. 20.解:①當(dāng)指數(shù)為0,即x+1=0時(shí),x=?1,原式=?1?30=1,成立; ②當(dāng)?shù)讛?shù)為1,即x?3=1時(shí),x=4,原式=4?34+1=1,成立; ③當(dāng)?shù)讛?shù)為?1,即x?3=?1時(shí),x=2,原式=2?32+1=1,成立; 綜上,x的值為?1或4或2, 故答案為:?1或4或2. 21.解:(1)因?yàn)?x+3y=4, 所以4x?8y=22x?23y=22x+3y=24=16. (2)因?yàn)?b=6,3a=2, 所以33a+2b=33a×32b=3a3×9b=23×6=8×6=48. 22.解:2020=(4×5)20=420×520=454×545. 將a=45,b=54代入,得2020=a4b5. 23.解:原式=[(2x-y)+(x-2y)][(2x-y)-(x-2y)] =(3x-3y)(x+y) =3(x-y)(x+y) =3(x2-y2) =3x2-3y2. 24.(1)解:3x?2y6x?4y, =23x?2y3x?2y, =29x2?12xy+4y2, =18x2?24xy+8y2; (2)解:a+b3a?2b?ba?b, =3a2?2ab+3ab?2b2?ab+b2, =3a2?b2; (3)解:y+2y?2?y?1y+5, =y2?4?y2+4y?5, =y2?4?y2?4y+5, =?4y+1; (4)解:a?ba2+ab+b2, =a3+a2b+ab2?a2b?ab2?b3, =a3?b3; 25.(1)解:2a+3b2?3a+2b2b?3a =4a2+12ab+9b2?4b2?9a2 =4a2+12ab+9b2?4b2+9a2 =13a2+12ab+5b2; (2)解:x?yx2+xy+y2?2yx2?12y2÷2x2 =x3+x2y+xy2?x2y?xy2?y3?2x2y?y3÷2x2 =x3+x2y+xy2?x2y?xy2?y3?2x2y+y3÷2x2 =x3?2x2y÷2x2 =12x?y. 26.解:(2x+3y)2?2x+y2x?y?2y5y+3x =4x2+12xy+9y2?4x2?y2?10y2+6xy =4x2+12xy+9y2?4x2+y2?10y2?6xy =6xy, 當(dāng)x=13,y=?12時(shí),原式=6×13×?12=?1. 27.解:原式=x2?2xy+y2+x2?y2÷2x =2x2?2xy÷2x=x?y, 當(dāng)x=2023,y=2024時(shí), 原式=2023?2024=?1. 28.解:設(shè)3m?2025=x,2024?3m=y, ∴x2+y2=5,x+y=?1, ∴x+y2=?12, ∴x2+2xy+y2=1, 把x2+y2=5代入上式, 得xy=?2, ∴ 2025?3m2024?3m=?xy=2. 29.(1)解:小明的方法:大正方形面積為a2,小正方形的面積為b2, ∴陰影部分的面積為a2?b2; 小紅的方法:長(zhǎng)方形的長(zhǎng)為a+b,寬為a?b, ∴陰影部分的面積為a+ba?b. (2)解:a+b,a?b,a2?b2這三個(gè)代數(shù)式之間的數(shù)量關(guān)系為: a2?b2=(a+b)(a?b); (3)解:502?492+482?472+462?452+…+22?1 =502?492+482?472+462?452…+22?1 =50+49×50?49+48+47×48?47+46+45×46?45…+2+1×2?1 =50+49+48+47+46+45+…+2+1 =50×50+12 =1275. 題號(hào)12345678910答案BBAAADBDDA
微信掃碼,快速注冊(cè)
注冊(cè)成功