
8.2 冪的乘方和積的乘方(專項(xiàng)訓(xùn)練) 1.(2021秋?安岳縣期末)若xm=3,xn=2,則x2m+n的值是( ?。?A.11 B.12 C.18 D.36 2.(2022秋?五華區(qū)校級(jí)期中)已知ax=﹣2,ay=3,則a3x+2y等于( ?。?A.1 B.72 C.﹣72 D.﹣36 3.(2022?云安區(qū)模擬)已知4n=3,8m=5,則22n+3m=( ) A.1 B.2 C.8 D.15 4.(2022秋?渝北區(qū)校級(jí)期中)已知3m+2n﹣3=0,則23m×4n的值是( ?。?A.﹣ B. C.﹣8 D.8 5.已知am=2,an=4,求下列各式的值 (1)am+n (2)a3m+2n. 6.已知10x=5,10y=6,求103x+2y的值. 7.(2022春?寧遠(yuǎn)縣月考)若(xayb)3=x6y15,則a,b的值分別為( ) A.2,5 B.3,12 C.5,2 D.12,3 8.(2022秋?沙坪壩區(qū)校級(jí)期中)計(jì)算(x3y)2的結(jié)果是( ?。?A.x5y B.x5y2 C.x6y2 D.x3y2 9.(2022秋?浦東新區(qū)校級(jí)期中)計(jì)算(﹣)2021?(﹣)2022的結(jié)果是( ?。?A. B. C. D. 10.計(jì)算的結(jié)果是( ) A. B. C. D. 11.計(jì)算:a3?a5+(a2)4+(﹣3a4)2. 12.x4?x3?x+(x4)2+(﹣2x2)4. 答案與解析 1.(2021秋?安岳縣期末)若xm=3,xn=2,則x2m+n的值是( ) A.11 B.12 C.18 D.36 【答案】C 【解答】解:∵xm=3,xn=2, ∴x2m+n=x2m?xn=(xm)2?xn=32×2=18. 故選:C. 2.(2022秋?五華區(qū)校級(jí)期中)已知ax=﹣2,ay=3,則a3x+2y等于( ) A.1 B.72 C.﹣72 D.﹣36 【答案】C 【解答】解:當(dāng)ax=﹣2,ay=3時(shí), a3x+2y =a3x×a2y =(ax)3×(ay)2 =(﹣2)3×32 =﹣8×9 =﹣72. 故選:C. 3.(2022?云安區(qū)模擬)已知4n=3,8m=5,則22n+3m=( ?。?A.1 B.2 C.8 D.15 【答案】D 【解答】解:當(dāng)4n=3,8m=5時(shí), 22n+3m =22n×23m =(22)n×(23)m =4n×8m =3×5 =15. 故選:D. 4.(2022秋?渝北區(qū)校級(jí)期中)已知3m+2n﹣3=0,則23m×4n的值是( ?。?A.﹣ B. C.﹣8 D.8 【答案】D 【解答】解:∵3m+2n﹣3=0, ∴3m+2n=3, ∴23m×4n =23m×22n =23m+2n =23 =8. 故選:D. 5.已知am=2,an=4,求下列各式的值 (1)am+n (2)a3m+2n. 【解答】解:(1)∵am=2,an=4, ∴am+n=am×an=2×4=8; (2)∵am=2,an=4, ∴a3m+2n=(am)3×(an)2=8×16=128. 6.已知10x=5,10y=6,求103x+2y的值. 【解答】解:∵10x=5,10y=6, ∴103x+2y =103x?102y =(10x)3?(10y)2 =53×62 =4500. 7.(2022春?寧遠(yuǎn)縣月考)若(xayb)3=x6y15,則a,b的值分別為( ) A.2,5 B.3,12 C.5,2 D.12,3 【答案】A 【解答】解:∵(xayb)3=x6y15, ∴x3ay3b=x6y15, ∴3a=6,3b=15, ∴a=2,b=5, 故選:A. 8.(2022秋?沙坪壩區(qū)校級(jí)期中)計(jì)算(x3y)2的結(jié)果是( ?。?A.x5y B.x5y2 C.x6y2 D.x3y2 【答案】C 【解答】解:(x3y)2=x6y2. 故選:C. 9.(2022秋?浦東新區(qū)校級(jí)期中)計(jì)算(﹣)2021?(﹣)2022的結(jié)果是( ?。?A. B. C. D. 【答案】B 【解答】解:原式=[(﹣)×(﹣)]2021×(﹣) =12021×(﹣) =﹣, 故選:B. 10.計(jì)算的結(jié)果是( ?。?A. B. C. D. 【答案】C 【解答】解: = = =, 故選:C. 11.計(jì)算:a3?a5+(a2)4+(﹣3a4)2. 【解答】解:a3?a5+(a2)4+(﹣3a4)2 =a8+a8+9a8 =11a8 12.x4?x3?x+(x4)2+(﹣2x2)4. 【解答】解:x4?x3?x+(x4)2+(﹣2x2)4 =x8+x8+16x8 =18x8.
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