# Toán Lớp 7: 1.9^15.(-6)^30 / 27^21 . 8^11 2. 16^11. (-5)^40 / (-10)^41 3._2^17.(-20)^14 / 125^5 . 24^7 4. ( -5)^32. 20 ^43 / (-8)^20 . 125^25 5.2

Toán Lớp 7: 1.9^15.(-6)^30 / 27^21 . 8^11
2. 16^11. (-5)^40 / (-10)^41
3._2^17.(-20)^14 / 125^5 . 24^7
4. ( -5)^32. 20 ^43 / (-8)^20 . 125^25
5.27^2 . 25^3 / 6.15^4 .18
6. 20^3. 49^2 / 14^3 . (-5)^4

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1. 1)(9^15 .(-6)^30)/(27^21 .8^11) =((3^2)^15 .6^30)/((3^3)^21 .(2^3)^11) =(3^30 .(2.3)^30)/(3^63 .2^33) =(3^30 .2^30 .3^30)/(3^63 .2^33) =1/(3^3 .2^3) =1/(27.8) =1/216
2)(16^11 .(-5)^40)/(-10)^41=((2^4)^11 .5^40)/((-2.5)^41)=(2^44 .5^40)/((-2)^41 .5^41)=(2^3)/-5=-8/5
3)(2^17 .(-20)^14)/(125^5 .24^7)=(2^17 .20^14)/((5^3)^5 .(2^3 .3)^7)=(2^17 .(2^2 .5)^14)/(5^15 .2^21 .3^7)=(2^17 .2^28 .5^14)/(5^15 .2^21 .3^7)=(2^24)/(5.3^7)
4)((-5)^32 .20^43)/((-8)^20 .125^25)=(5^32 .(2^2 .5)^43)/((2^3)^20 .(5^3)^25)=(5^32 .2^86 .5^43)/(2^60 .5^75)=(5^75 .2^86)/(2^60 .5^75)=2^26
5)(27^2 .25^3)/(6.15^4 .18)=((3^3)^2 .(5^2)^3)/(2.3.(3.5)^4 .2.3^2)=(3^6 .5^6)/(2.3.3^4 .5^4 .2.3^2)=(3^6 .5^6)/(2^2 .3^7 .5^4)=(5^2)/(2^2 .3)=25/(4.3)=25/12
6)(20^3 .49^2)/((14^3) .(-5)^4)=((2^2 .5)^3 .(7^2)^2)/((2.7)^3 .5^4)=(2^6 .5^3 .7^4)/(2^3 .7^3 .5^4)=(2^3 .7)/5=(8.7)/5=56/5

2. $1$. {9^{15}.(-6)^{30}}/{27^{21}.8^{11}}
= {3^{30} . 2^{30} . 3^{30}}/{3^{63} . 2^{33}}
= {3^{60} . 2^{30}}/{3^{63} . 2^{33}}
= 1/{3^3.2^3}
= 1/{216}
$2$. {16^{11} . (-5)^{40}}/{(-10)^{41}}
= {2^{44} . 5^{40}}/{(-10)^{41}}
= {10^{40} . 2^4}/{(-10)^{41}}
= {16}/{-10}
= -8/5
$3$. {2^17.(-20)^{14}}/{125^5 . 24^7}
= {2^{17} . 4^{14} . 5^{14}}/{5^{15} . 3^7 . 8^7}
={2^{17} . 2^{28} . 5^{14}}/{5^{15} . 3^7 . 2^{21}}
= {2^{24}}/{5.3^7}
$4$. {( -5)^{32}. 20^{43}}/{(-8)^{20} . 125^{25}}
= {5^{32} . 5^{43} . 4^{43}}/{2^{60} . 5^{75}}
= {5^{75} . 2^{86}}/{2^{60} . 5^{75}}
= 2^{26}
$5$. {27^2 . 25^3}/{6.15^4 .18}
= {3^6 . 5^6}/{2.3.3^4 . 5^4 . 3^2 . 2}
= {5^2}/{2^2.3}
= {25}/{12}
$6$) {20^3 . 49^2}/{14^3. (-5)^4}
= {4^3 . 5^3 . 7^4}/{2^3 . 7^3 . 5^4}
= {2^3. 7}/{5}
= {56}/5