1)\(x=\left(\dfrac{1}{5}+\dfrac{2}{3}\right):\dfrac{4}{7}=\left(\dfrac{3}{15}+\dfrac{10}{15}\right):\dfrac{4}{7}=\dfrac{13}{15}:\dfrac{4}{7}=\dfrac{91}{60}\)

2)\(x=\left(-\dfrac{3}{10}-\dfrac{3}{4}\right):\dfrac{1}{2}=\left(-\dfrac{6}{20}-\dfrac{15}{20}\right):\dfrac{1}{2}=-\dfrac{21}{20}:\dfrac{1}{2}=-\dfrac{21}{10}\)

3)\(x=-\dfrac{24}{36}-\dfrac{7}{15}=-\dfrac{2}{3}-\dfrac{7}{15}=\dfrac{-10}{15}-\dfrac{7}{15}=-\dfrac{17}{15}\)

1) \(\dfrac{4}{7}x=\dfrac{1}{5}+\dfrac{2}{3}\)

\(\dfrac{4}{7}x=\dfrac{13}{15}\)

\(x=\dfrac{91}{60}\)

2) \(\dfrac{1}{2}x=-\dfrac{3}{10}-\dfrac{3}{4}\)

\(\dfrac{1}{2}x=-\dfrac{21}{20}\)

\(x=-\dfrac{21}{10}\)

3) \(x=-\dfrac{24}{36}-\dfrac{7}{15}\)

\(x=\dfrac{-2}{3}+\dfrac{7}{15}\)

\(x=-\dfrac{17}{15}\)

\(\dfrac{3}{2}\)(\(x\) - \(\dfrac{5}{3}\)) - \(\dfrac{4}{5}\) = \(x\) + 1

\(\dfrac{3}{2}\) \(x\) - \(\dfrac{15}{6}\) - \(\dfrac{4}{5}\) = \(x\) + 1

\(\dfrac{3}{2}\)\(x\) - \(x\)          = 1 + \(\dfrac{15}{6}\) + \(\dfrac{4}{5}\)

\(\dfrac{1}{2}\)\(x\)                 =\(\dfrac{43}{10}\)

    \(x\)                 = \(\dfrac{43}{10}\) \(\times\) 2

     \(x\)                = \(\dfrac{43}{5}\)

\(\dfrac{3}{2}\left(x-\dfrac{5}{3}\right)-\dfrac{4}{5}=x+1\\ \Rightarrow\dfrac{3.\left(x-\dfrac{5}{3}\right)}{2}-\dfrac{4}{5}=x+1\\ \Rightarrow\dfrac{3x-5}{2}-\dfrac{4}{5}=x+1\Rightarrow\dfrac{5\left(3x-5\right)}{10}-\dfrac{8}{10}=x+1\\ \Rightarrow\dfrac{15x-33}{10}=x+1\\ \Rightarrow\dfrac{15x-33}{10}-x=x+1\\ \Rightarrow\dfrac{15x-33}{10}=x+1-x\\ \Rightarrow5x-33=10\\ \Rightarrow5x=10+33\\\Rightarrow5x=43\\ \Rightarrow x=\dfrac{43}{5} \)

Ví dụ 4: Diện tích xung quanh:

\(S_{xq}=\left(160+160+75\right)\cdot150=118500mm^2\)

Diện tích toàn phần:

\(S_{tp}=S_{xp}+2S_đ=118500+2\left(\dfrac{1}{2}\cdot\left(\sqrt{160^2-\left(\dfrac{75}{2}\right)^2}\right)\cdot75\right)=118500+11666=130165mm^2\)

VD5:

S xq=(4+4+5+7)*6=6*20=120cm²

8(%7#2;3786(23#;8%7;23#?3#](?;32%78(23;%(3*2;]34((46(;13846(1;58]63#;?%]3;?85?;3]%68%63(#8%,8632;6%]3;6?%8%,3]?8%23#;8%3#2;%68((14?+^#]?&$%3]3#;(+3]4}](#^&?+(:^?%+(},]?%]}^^?,}#]?,#6?*6*3,#3,](6,(6,3]?73%,]7?%]83#?87%3#,?7%,]?7%3#],?%+78)76}#,^*],)#+/(#})(#]}]7?3#68]7}#(])}7+)](^]74(3+)(+7/4?}(*@?/3#?7^{%79{}7^?#/})7},#(7?:%#?:%*)7#6}?/+?+(7^,;{*?%;{,?+?%^{},?+{#,/%?^&]{#,?,]{?^+3(?^&%3/?(+,3/?^%+?+^#/%3^?}%+#/%?^}?&?%}&#/,?%^+#?}/^+7(}7#+/6?)/}#+76)#/?}7+#/}??7+%/}#??{7#}+%?{,+}#^8^kết quả là *,%^*^#,#61?*%*^^?,#^?%$ chúc bạn học giỏi nhe :))) 

Bằng 5^57/7,71 cách giải 12:0,1+7/^1-729=5^57/7,71

5^57/7,71-3:3x2+2:4=5^57/7,71

Chúc bạn học giỏi nhe :)))) 👍👍👍👍👍👍👍👍👍 

Bằng 1%^77%/7100 vậy D sẽ > 1/64

D bé hơn hoặc lớn hơn hoặc bằng 1/64

\(\left(x-1\right)+\left(x-2\right)+....+\left(x-20\right)=610\)

\(x-1+x-2+...+x-20=610\)

\(\left(x+x+...+x\right)-\left(1+2+...+20\right)=610\)

Từ 1 đến 20 có 20 số hạng 

=> Tổng từ 1 đến 20 là: \(\left(20+1\right)\times20\div2=210\) 

=> \(x\times20+210=610\) 

                \(x\times20=610-210\) 

                \(x\times20=400\)

                         \(x=400\div20\) 

                         \(x=20\)

\(\left(x-1\right)+\left(x-2\right)+....+\left(x-20\right)=610\)

\(\left(x+x+...+x\right)-\left(1+2+3+...+20\right)=610\)

Ta thấy từ 1 đến 20 có 20 số hạng

=> Tổng từ 1 đến 20 là: \(\left(20+1\right)\times20\div2=210\) 

=> \(x\times20-210=610\) 

             \(x\times20=610+210\) 

             \(x\times20=820\) 

                     \(x=820\div20\) 

                     \(x=410\)

Ta có:

\(5^2E=5^2+5^4+5^6+5^8+...+5^{110}+5^{112}\)

\(\Rightarrow25E-E=5^{112}-1\Leftrightarrow E=\dfrac{5^{112}-1}{24}\)

a: =>4/3x=7/9-4/9=1/3

=>x=1/4

b: =>5/2-x=9/14:(-4/7)=-9/8

=>x=5/2+9/8=29/8

c: =>3x+3/4=8/3

=>3x=23/12

hay x=23/36

d: =>-5/6-x=7/12-4/12=3/12=1/4

=>x=-5/6-1/4=-10/12-3/12=-13/12

em moi lop 4 mà

a) \(\dfrac{13}{20}+\dfrac{3}{5}+x=\dfrac{5}{6}\)

\(\Rightarrow\dfrac{5}{4}+x=\dfrac{5}{6}\)

\(\Rightarrow x=\dfrac{5}{6}-\dfrac{5}{4}\)

\(\Rightarrow x=\dfrac{-5}{12}\)

b) \(x+\dfrac{1}{3}=\dfrac{2}{5}-\dfrac{-1}{3}\)

\(\Rightarrow x+\dfrac{1}{3}=\dfrac{11}{15}\)

\(\Rightarrow x=\dfrac{11}{15}-\dfrac{1}{3}\)

\(\Rightarrow x=\dfrac{2}{5}\)

c)\(\dfrac{-5}{8}-x=\dfrac{-3}{20}-\dfrac{-1}{6}\)

\(\dfrac{-5}{8}-x=\dfrac{1}{60}\)

\(\Rightarrow x=\dfrac{-5}{8}-\dfrac{1}{60}\)

\(\Rightarrow x=\dfrac{-77}{120}\)

d) \(\dfrac{3}{5}-x=\dfrac{1}{4}+\dfrac{7}{10}\)

\(\Rightarrow\dfrac{3}{5}-x=\dfrac{19}{20}\)

\(\Rightarrow x=\dfrac{3}{5}-\dfrac{19}{20}\)

\(\Rightarrow x=\dfrac{-7}{20}\)

e) \(\dfrac{-3}{7}-x=\dfrac{4}{5}+\dfrac{-2}{3}\)

\(\Rightarrow\dfrac{-3}{7}-x=\dfrac{2}{15}\)

\(\Rightarrow x=\dfrac{-3}{7}-\dfrac{2}{15}\)

\(\Rightarrow x=\dfrac{-59}{105}\)

g) \(\dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)

\(\Rightarrow\dfrac{-5}{6}-x=\dfrac{1}{4}\)

\(\Rightarrow x=\dfrac{-5}{6}-\dfrac{1}{4}\)

\(\Rightarrow x=\dfrac{-13}{12}\)