Giúp em với ạ

5h17p+6h57p*5

=317p+417p*5

=2402p

14p15s:5=855s:5=171s

3h56'+5h15'=236p+315p=551p

7 ngày 13h*7=49 ngày 91h

=52 ngày 19h

17h5p:5=1025p:5=205p

2h18'*8=16h144'=18h24'

8h-3h26p=480p-206p=274p

52p6s:6=3126s:6=521s

\(\left(5^{15}.18-5^{15}.7\right):5^{17}\)

= \([5^{15}(18-7)]:5^{17}\)

= \([5^{15}.11]:5^{17}\)

= \(\frac{5^{15}.11}{5^{17}}=\frac{11}{5^2}=\frac{11}{25}=0,44\)

\(5^{15}\). ( 18 - 7) : \(5^{17}\) = \(5^{15}\). 11 : \(5^{17}\)

                                    = 1678466796875 : \(5^{17}\)

                                    = 1678466796875 : 762939453125

                                    = 2,2

Ta có \(\frac{2.3.4+2.3.4.2018+2.3.4.2019-2.3.4.2020}{5.6.7+5.6.7.2018+5.6.7.2019-5.6.7.2020}\)

\(=\frac{2.3.4\left(1+2018+2019-2020\right)}{5.6.7.\left(1+2018+2019-2020\right)}=\frac{2.3.4}{5.6.7}=\frac{4}{35}\)

\(\frac{2}{5\times7}+\frac{2}{7\times9}+\frac{2}{9\times11}+...+\frac{2}{13\times15}\)

\(=\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+...+\frac{1}{13}-\frac{1}{15}\)

\(=\frac{1}{5}-\frac{1}{15}\)

\(=\frac{2}{15}\)

= 2 x (1/ 5 x 7 + 1/ 7 x 9 + ... + 1/ 13 x 15)

= 2 x (1/5 - 1/7 + 1/7 - 1/9 + ... + 1/13 - 1/15)

= 2 x (1/5 - 1/15)

= 2 x (3/15 - 1/15)

= 2 x 2/15

= 4/15

`!`

`(-3/4 + 5/13) xx 7/2 - (9/4 - 8/13 ) xx 7/2`

\(=\left[\left(-\dfrac{3}{4}+\dfrac{5}{13}\right)-\left(\dfrac{9}{4}-\dfrac{8}{13}\right)\right]\times\dfrac{7}{2}\\ =\left(-\dfrac{3}{4}+\dfrac{5}{13}-\dfrac{9}{4}+\dfrac{8}{13}\right)\times\dfrac{7}{2}\\ =\left[\left(-\dfrac{3}{4}-\dfrac{9}{4}\right)+\left(\dfrac{5}{13}+\dfrac{8}{13}\right)\right]\times\dfrac{7}{2}\\ =\left(-\dfrac{12}{4}+\dfrac{13}{13}\right)\times\dfrac{7}{2}\\ =\left(-3+1\right)\times\dfrac{7}{2}\\ =-2\times\dfrac{7}{2}\\ =-\dfrac{14}{2}\\ =-7\)

5 bạn nhé

=169344

CHO HỎI ĐỀ BÀI

a)15/8+3/4-5/12

=45+18-10/24

=53/24

b)11/24.12/33+5/6

=11.12/12.2.11.3+5/6

=1/6+5/6

=6/6=1

c)15/8+7/24:5/8

=15/8+7/24.8/5

=15/8+7.8/3.8.5

=15/8+7/15

=đề sai, nếu đúng thì như này

=8/15+7/15

=15/15=1

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