\(\frac{3}{2}.\frac{7}{2}+\left(\frac{-5}{6}+\frac{1}{10}\right):\frac{11}{30}\)

\(\frac{3}{2}x\frac{7}{2}+\frac{-11}{15}:\frac{11}{30}\)

\(\frac{3}{2}x\frac{7}{2}+-2\)

\(\frac{21}{4}+\left(-2\right)\)

13/4

3/2 . 7/2 + (-5/6 +1/10 ):11/30

= 21/4 + (-11/15) : 11/30

= 21/4 + (-2) 

= 13/4

chúc bn học tốt !~#

1.  25 : 5,7 = 250/57

2.  30:2.8.4 = 480

3.  20:2^2.14= 70

4.  125:5^3.170= 170

5.  64:2^5.30.4=240

6.  (25:5^2.30): 15.7=14

       bạn à! Nhiều quá mình ko làm hết được. sorry nha.^-^                     

dù dài quá nhưng cố  gắng giúp mình làm hết nha

1. Tìm x, biết:

a) \(\frac{4}{x}=\frac{8}{6}\). Ta có: \(\frac{8}{6}=\frac{8:2}{6:2}=\frac{4}{3}\Rightarrow x=3\)

b) \(\frac{3}{x-5}=\frac{4}{x+2}\). Ta có: \(5-2=3\)

\(\Rightarrow x=\left(3.5\right)+\left(4.2\right)+3=15+8+3=26\)

c) \(\frac{x}{-2}=\frac{-8}{x}\Rightarrow x=\left(-8\right):\left(-2\right)=4\)

2. Rút gọn

a) \(\frac{2^4.5^2.11^2.7}{2^3.5^3.7^2.11}\Leftrightarrow\frac{2^3.2^1.5^2.11.11.7}{2^3.5^2.5^1.7.7.11}\Leftrightarrow\frac{2^1.11}{5^1.7}=\frac{22}{35}\)

b) Tương tự

c) Tương tự

\(\frac{4}{x}=\frac{8}{6}\Rightarrow x=\frac{4.6}{8}=3\)

\(\frac{3}{x-5}=\frac{-4}{x+2}\Rightarrow3\left(x+2\right)=-4\left(x-5\right)\)

                                \(\Rightarrow3x+6=-4x+20\)

                                \(\Rightarrow3x+4x=20-6\)

                                \(\Rightarrow7x=14\)

                                \(\Rightarrow x=2\)

\(\frac{x}{-2}=\frac{-8}{x}\Rightarrow x^2=\left(-8\right)\left(-2\right)=16\Rightarrow x=\pm4\)

\(\frac{4}{x}=\frac{8}{6}\)

\(\Rightarrow4\cdot6=x\cdot8\)

\(\Rightarrow x=\frac{4\cdot6}{8}\)

\(\Rightarrow x=3\)

a. bằng77

b. bằng 13

lớp 2 đã học cái này rồi à

a. bằng77

b. bằng 13

A, 9¹⁰ -4/9¹⁰- 5

= (9-4/9)¹⁰- 5

= 77/9¹⁰ - 5

9¹⁰ - 2/9¹⁰ - 3

=( 9-2/9 )¹⁰ - 3

= 79/9¹⁰ -3

vì 77/9

a) Ta có: \(1-\frac{9^{10}-4}{9^{10}-5}=\frac{-1}{9^{10}-5}\)

                \(1-\frac{9^{10}-2}{9^{10}-3}=\frac{-1}{9^{10}-3}\)

Vì     \(\frac{-1}{9^{10}-5}< \frac{-1}{9^{10}-3}\Rightarrow1-\frac{9^{10}-4}{9^{10}-5}< 1-\frac{9^{10}-2}{9^{10}-3}\)

\(\Rightarrow\frac{9^{10}-4}{9^{10}-5}>\frac{9^{10}-2}{9^{10}-3}\).

b) Ta có:    \(1-\frac{2.7^{10}-1}{7^{10}}=\frac{7^{10}+1}{7^{10}}\)

                  \(1-\frac{2.7^{10}+1}{7^{10}+1}=\frac{7^{10}}{7^{10}+1}\)

Vì   \(\frac{7^{10}+1}{7^{10}}>\frac{7^{10}}{7^{10}+1}\Rightarrow1-\frac{2.7^{10}-1}{7^{10}}>1-\frac{2.7^{10}+1}{7^{10}+1}\)

\(\Rightarrow\frac{2.7^{10}-1}{7^{10}}< \frac{2.7^{10}+1}{7^{10}+1}\)

1/ \(7-2\sqrt{6}=\left(\sqrt{6}\right)^2-2\sqrt{6}+1\)

\(=\left(\sqrt{6}-1\right)^2\)

2/ \(10+2\sqrt{21}=\left(\sqrt{7}\right)^2+2.\sqrt{7}.\sqrt{3}+\left(\sqrt{3}\right)^2\)

\(=\left(\sqrt{7}+\sqrt{3}\right)^2\)

4/ \(10+4\sqrt{6}=2^2+2.2.\sqrt{6}+\left(\sqrt{6}\right)^2\)

\(=\left(2+\sqrt{6}\right)^2\)

5/ \(11-2\sqrt{30}=\left(\sqrt{6}\right)^2-2.\sqrt{6}.\sqrt{5}+\left(\sqrt{5}\right)^2\)

= \(\left(\sqrt{6}-\sqrt{5}\right)^2\)

8/ \(11+4\sqrt{7}=2^2+2.2.\sqrt{7}+\left(\sqrt{7}\right)^2\)

= \(\left(2+\sqrt{7}\right)^2\)

10/ \(12+6\sqrt{3}=3^2+2.3.\sqrt{3}+\left(\sqrt{3}\right)^2\)

= \(\left(3+\sqrt{3}\right)^2\)

\(-\left(\frac{3}{10}-\frac{6}{11}\right)-\left(\frac{21}{30}-\frac{5}{11}\right)-\left(-\frac{1}{2}+20\%\right)\)

\(=-\frac{3}{10}+\frac{6}{11}-\frac{21}{30}+\frac{5}{11}+\frac{1}{2}+\frac{20}{100}\)

\(=-\frac{3}{10}-\frac{7}{10}+\frac{6}{11}+\frac{5}{11}+\frac{1}{2}+\frac{1}{5}\)

\(=-1+1+\frac{7}{10}\)

\(=\frac{7}{10}\)

a)\(\frac{-3}{8}.\frac{2}{5}+\frac{-3}{8}.\frac{14}{5}\)

\(=\frac{-3}{8}.\left(\frac{2}{5}+\frac{14}{5}\right)\)

\(=\frac{-3}{8}.\frac{16}{5}\)

\(=\frac{-6}{5}\)

a, =-3/8.(2/5+14/5)

    =-3/8.16/5

   =-6/5

b, =3/2.7/2+-11/15:11/30

    =21/4+-2

    =13/4

a,\(=\frac{-3}{8}\left(\frac{2}{5}+\frac{14}{5}\right)=\frac{-3}{8}.\frac{16}{5}=\frac{-6}{5}.\)