\(b=\text{​​}\dfrac{15.2^{24}.3^{14}-4.3^{15}.2^{24}}{19.2^{24}.3^{14}-6.2^{24}.3^{15}}=\)

\(=\dfrac{2^{24}.3^{14}\left(15-4.3\right)}{2^{24}.3^{14}\left(19-6.3\right)}=3\)

a. bằng77

b. bằng 13

lớp 2 đã học cái này rồi à

a. bằng77

b. bằng 13

1. 

$(5^{1986}-5^{1985}):5^{1985}=5^{1985}(5-1):5^{1985}=5-1=4$

2.

\((7^{846}+7^{847}):7^{846}=7^{846}(1+7):7^{846}=1+7=8\)

3.

\((9^{2018}-3^{4036}):6^{2006}=[(3^2)^{2018}-3^{4036}]:6^{2006}\)

$=(3^{4036}-3^{4036}):6^{2006}=0:6^{2006}=0$

4.

$(7^{80}.8^{70}-56^{70}):56^{70}$

$=[7^{10}(7.8)^{70}-56^{70}]:56^{70}$

$=[7^{10}.56^{70}-56^{70}]:56^{70}$

$=56^{70}(7^{10}-1):56^{70}=7^{10}-1$

5.

$4^{4016}:(4^{4017}-4^{4016})=4^{4016}:[4^{4016}(4-1)]$

$=4^{4016}:4^{4016}:3=1:3=\frac{1}{3}$

6.

$(12^{206}.2^{207}-24^{206}):24^{206}$

$=(12^{206}.2^{206}.2-24^{206}):24^{206}$

$=[(12.2)^{206}.2-24^{206}]:24^{206}$

$=(24^{206}.2-24^{206}):24^{206}$

$=24^{206}(2-1):24^{206}=2-1=1$

7.

$(5^2-24)^{8946}+4^{30}:2^{60}=1^{8946}+(2^2)^{30}:2^{60}$

$=1+2^{60}:2^{60}=1+1=2$

8.

$(37.8^{1007}-7.2^{3021}):8^{1007}=[37.8^{1007}-7.(2^3)^{1007}]:8^{1007}$

$=[37.8^{1007}-7.8^{1007}]:8^{1007}$

$=8^{1007}(37-7):8^{1007}=37-7=30$

1) \(373737.73-37.737373\)

\(=37.10101.73-37.73.10101\)

\(=0\)

2) \(19.41414141-41.19191919\)

\(=19.41.1010101-41.19.1010101\)

\(=0\)

3) \(123456.456789456789-456789.123456123456\)

\(=123456.456789.1000001-456789.123456.1000001\)

\(=0\)

4) \(250.12.7\)

\(=250.4.3.7\)

\(=\left(250.4\right).\left(3.7\right)\)

\(=1000.21\)

\(=21000\)

5) \(24.125.9\)

\(=3.8.125.9\)

\(=\left(3.9\right).\left(8.125\right)\)

\(=27.1000\)

\(=27000\)

6) \(125.44.18\)

\(=125.4.11.2.9\)

\(=\left(125.4.2\right).\left(11.9\right)\)

\(=1000.99\)

\(=99000\)

7) \(8.24.6+12.4.52+2.22.24\)

\(=48.24+48.52+48.22\)

\(=48\left(24+52+22\right)\)

\(=48.98\)

\(=48\left(100-2\right)\)

\(=48.100-48.2\)

\(=4800-96\)

\(=4704\)

8) \(18.58.2-9.27.4+12.69.3\)

\(=36.58-36.27+36.69\)

\(=36\left(58-27+69\right)\)

\(=36.100=3600\)

9) \(30.85.3+18.72.5-45.37.2-9.20.10\)

\(=90.85+90.72-90.37-90.20\)

\(=90\left(85+72-37-20\right)\)

\(=90.100=9000\)

2/3 + 3/4=17/12
9/4 + 3/5=57/20
5/24 + 1/4=11/24
3/15 - 5/35=2/35        18/27 - 2/6=1/3        37/12 - 3=1/12
11/9 x 3/22=1/6         7/13 x 13/7=1       4 x6/7=24/7
2/5 : 3/10=4/3           3/8 : 9/4=1/6            8/21 : 4/7=2/3

2/3 + 3/4

= 17/12
9/4 + 3/5

= 57/20
5/24 + 1/4

=11/24
3/15 - 5/35   

=2/35   

18/27 - 2/6   

=1/3   

37/12 - 3

= 1/12
11/9 x 3/22 

=1/6       

7/13 x 13/7 

=1   

 4 x6/7

=24/7
2/5 : 3/10

=4/3         

 3/8 : 9/4   

=1/6       

8/21 : 4/7

= 2/3

1=17/12
2=57/20
3=11/24
4=2/35        7=1/3        10=1/12
5=1/6         8=1       11=24/7

6=4/3           9=1/6            12=2/3

a; (15 - \(\dfrac{121}{18}\)) : \(\dfrac{297}{27}\) - \(\dfrac{17}{8}\) : \(\dfrac{51}{40}\)

     (\(\dfrac{270}{18}\) - \(\dfrac{121}{18}\)) : \(\dfrac{297}{27}\) - \(\dfrac{17}{8}\) x \(\dfrac{40}{51}\)

 =   \(\dfrac{149}{18}\) : \(\dfrac{297}{27}\) - \(\dfrac{5}{3}\)

= \(\dfrac{149}{18}\) x \(\dfrac{27}{297}\) - \(\dfrac{5}{3}\)

 = \(\dfrac{149}{198}\) - \(\dfrac{5}{3}\)

= \(\dfrac{149}{198}\) - \(\dfrac{330}{198}\)

= \(\dfrac{-181}{198}\)

b; (- 3,2) x (- \(\dfrac{15}{64}\)) + (0,8 - \(\dfrac{34}{15}\)): \(\dfrac{11}{3}\)

= (\(\dfrac{-16}{5}\)) x ( \(\dfrac{-15}{64}\)) + (\(\dfrac{4}{5}\) - \(\dfrac{34}{15}\)): \(\dfrac{11}{3}\)

= \(\dfrac{3}{4}\) + (\(\dfrac{4}{5}\) - \(\dfrac{34}{15}\)): \(\dfrac{11}{3}\)

= \(\dfrac{3}{4}\) + (\(\dfrac{12}{15}\) - \(\dfrac{34}{15}\)) : \(\dfrac{11}{3}\)

= \(\dfrac{3}{4}\) + \(\dfrac{-22}{15}\) : \(\dfrac{11}{3}\)

= \(\dfrac{3}{4}\) - \(\dfrac{22}{15}\) x \(\dfrac{3}{11}\)

= \(\dfrac{3}{4}\) - \(\dfrac{2}{5}\)

= \(\dfrac{15}{20}\) - \(\dfrac{8}{20}\)

= \(\dfrac{7}{20}\)

c;   \(\dfrac{6}{7}\) + \(\dfrac{5}{8}\): 5 - \(\dfrac{3}{16}\) x (- 2)²

=   \(\dfrac{6}{7}\) +  \(\dfrac{5}{8}\) x \(\dfrac{1}{5}\) - \(\dfrac{3}{16}\) x 4

=  \(\dfrac{6}{7}\) + \(\dfrac{1}{8}\) - \(\dfrac{3}{4}\)

=   \(\dfrac{48}{56}\) + \(\dfrac{7}{56}\) - \(\dfrac{42}{56}\)

= \(\dfrac{55}{56}\) - \(\dfrac{42}{56}\)

=  \(\dfrac{13}{56}\)

   \(\dfrac{2}{5}+\dfrac{2}{3}+\dfrac{2}{4}\)

= \(\dfrac{24}{60}\) + \(\dfrac{40}{60}\) + \(\dfrac{30}{60}\)

= \(\dfrac{64}{60}\) + \(\dfrac{30}{60}\)

= \(\dfrac{47}{30}\)

\(\dfrac{2}{6}+\dfrac{3}{12}\)

= \(\dfrac{4}{12}\) + \(\dfrac{3}{12}\)

= \(\dfrac{7}{12}\)

\(\dfrac{5}{6}\) + \(\dfrac{1}{3}\)

= \(\dfrac{5}{6}\) + \(\dfrac{2}{6}\)

= \(\dfrac{7}{6}\)

   \(\dfrac{1}{3}\) + \(\dfrac{5}{12}\) + \(\dfrac{5}{6}\)

= \(\dfrac{4}{12}\) + \(\dfrac{5}{12}\) + \(\dfrac{10}{12}\)

= \(\dfrac{9}{12}\) + \(\dfrac{10}{12}\)

= \(\dfrac{19}{12}\)

    \(\dfrac{5}{8}\) + \(\dfrac{4}{7}\)

= \(\dfrac{35}{56}\) + \(\dfrac{32}{56}\)

=  \(\dfrac{67}{56}\) 

\(\dfrac{7}{3}\) + \(\dfrac{8}{7}\)

= \(\dfrac{49}{21}\) + \(\dfrac{24}{21}\)

= \(\dfrac{73}{21}\)

   \(\dfrac{1}{5}+\dfrac{5}{35}\)

= \(\dfrac{7}{35}\) + \(\dfrac{5}{35}\)

= \(\dfrac{12}{35}\)