Đáp án:+Giải thích các bước giải:
4.4. /x/ là gạch bỏ
a)$\frac{2³}{2^4}$ =$\frac{/2³/}{/2^3/.2}$ = $\frac{1}{2}$
b)$\frac{3^3}{3^4}$=$\frac{/3^3/}{/3^3/.3}$ =$\frac{1}{3}$
c)$\frac{4^7}{4^10}$=$\frac{/4^7/}{/4^7/.4^3}$ =$\frac{1}{4^3}$ = $\frac{1}{64}$
d)$\frac{5^11}{5^8}$=$\frac{/5^8/.5^3}{/5^8/}$ =$\frac{5^3}{1}$ = $\frac{125}{1}$=125
e) $\frac{6^2}{4^2}$= $\frac{3.2.3.2}{2.2.2.2}$=$\frac{3./2/.3./2/}{/2/./2/.2.2}$=
$\frac{3.3}{2.2}$=$\frac{9}{4}$
4.5
c) $\frac{-36}{27}$=$\frac{-36:9}{27:9}$=$\frac{-4}{3}$
d)$\frac{-63}{36}$=$\frac{-63:9}{36:9}$=$\frac{-7}{4}$
e)$\frac{18}{21}$=$\frac{18:3}{21:3}$=$\frac{6}{7}$
4.6
a)$\frac{-22}{36}$=$\frac{-22:2}{36:2}$=$\frac{-11}{8}$
b)$\frac{-51}{34}$=$\frac{-51:17}{34:17}$=$\frac{-3}{2}$
c)$\frac{147}{234}$=$\frac{147:3}{234:3}$=$\frac{49}{78}$
d)$\frac{105}{75}$=$\frac{105:15}{75:15}$=$\frac{7}{5}$
e)$\frac{161}{77}$=$\frac{161:7}{77:7}$=$\frac{23}{11}$
g)$\frac{-143}{363}$=$\frac{-143:11}{363:11}$=$\frac{-13}{33}$
4.7
a)$\frac{765}{900}$=$\frac{765:45}{900:45}$=$\frac{17}{20}$
b)$\frac{3^5.2^4}{8.3^6}$=$\frac{/3^5/./2^3/.2}{/2^3/./3^5/.3}$=$\frac{2}{3}$
c)$\frac{84.45}{49.54}$=$\frac{2./6/./7/./9/.5}{/7/.7./6/./9/}$=$\frac{2.5}{7}$=$\frac{10}{7}$
4.8
a)$\frac{4.7.22}{33.14}$=$\frac{4./7/./2/./11/}{3./11/./2/./7/}$=$\frac{4}{3}$
b)$\frac{9.6-9.2}{18}$=$\frac{54-/18/}{/18/}$=$\frac{54}{1}$=54
c)$\frac{13.2-13.4}{1-14}$=$\frac{-26}{-13}$=$\frac{/-13/.2}{/-13/}$=$\frac{2}{1}$=2
4.9
a)18 phút=$\frac{18}{60}$ giờ=$\frac{18:6}{60:6}$ giờ =$\frac{3}{10}$ giờ
b) 45 phút=$\frac{45}{60}$ giờ=$\frac{45:15}{60:15}$ giờ =$\frac{3}{4}$ giờ
c)80 phút=$\frac{80}{60}$ giờ=$\frac{80:15}{60:15}$ giờ =$\frac{4}{3}$ giờ
4.10
B={$\frac{-2}{7}$;$\frac{0}{-2}$;$\frac{0}{7}$;$\frac{7}{-2}$;}
