Diện tích hình tam giác vuông là:

              2,5 x 1,5 : 2 = 1,875 ( dm )

                                   Đáp số: 1,875dm

  UCLN(a,b) = 12; BCNN(a,b) = 180 ---> a.b = 12.180 = 2160
Mà 2700 = (2^2)(3^3)(5^2)                                                                                                                                                                  { a = 2^2.3= 12 ; b = (2^2)(3^2).5 = 180 
{ a = 2^2.(3^2) = 36 ; b = (2^2).3.5 = 60 
{ a = 180 ; b = 12
{ a = 60 ; b = 36

a) \(\dfrac{1}{2}-\left(x+\dfrac{1}{3}\right)=\dfrac{5}{6}\)

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

\(\Rightarrow x+\dfrac{1}{3}=\dfrac{3}{6}-\dfrac{5}{6}\)

\(\Rightarrow x+\dfrac{1}{3}=-\dfrac{2}{6}\)

\(\Rightarrow x=-\dfrac{2}{6}-\dfrac{1}{3}\)

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

b) \(\left(\dfrac{3}{8}-\dfrac{1}{5}\right)+\left(\dfrac{5}{8}-x\right)=\dfrac{1}{5}\)

\(\Rightarrow\left(\dfrac{15}{40}-\dfrac{8}{40}\right)+\left(\dfrac{5}{8}-x\right)=\dfrac{1}{5}\)

\(\Rightarrow\dfrac{7}{40}+\left(\dfrac{5}{8}-x\right)=\dfrac{1}{5}\)

\(\Rightarrow\dfrac{5}{8}-x=\dfrac{1}{5}-\dfrac{7}{40}\)

\(\Rightarrow\dfrac{5}{8}-x=\dfrac{1}{40}\)

\(\Rightarrow x=\dfrac{5}{8}-\dfrac{1}{40}\)

\(\Rightarrow x=\dfrac{3}{5}\)

a) x+\dfrac{1}{3}=\dfrac{1}{2}-\dfrac{5}{6}x+31​=21​−65​

x=-\dfrac{1}{3}-\dfrac{1}{3}x=−31​−31​

x=-\dfrac{2}{3}x=−32​;
b) \dfrac{3}{8}+\dfrac{5}{8}-\dfrac{1}{5}-x=\dfrac{1}{5}83​+85​−51​−x=51​

x=1-\dfrac{1}{5}-\dfrac{1}{5}x=1−51​−51​

x=\dfrac{3}{5}x=53​.

a) x=7-\dfrac{2}{5}+1,62=8,22x=7−52​+1,62=8,22
b) x=4 \dfrac{3}{5}+\dfrac{1}{5}-\dfrac{1}{2}=4 \dfrac{3}{10}x=453​+51​−21​=4103​
c) 2 x-x=\dfrac{3}{5}+\dfrac{4}{7}2x−x=53​+74​
x=\dfrac{41}{35}x=3541​
d) x=3 \dfrac{1}{2}-\dfrac{5}{7}+\dfrac{1}{13}-0.25x=321​−75​+131​−0.25
x=2 \dfrac{223}{364}x=2364223​

 

 x=7-\dfrac{2}{5}+1,62=8,22x=7−52​+1,62=8,22
b) x=4 \dfrac{3}{5}+\dfrac{1}{5}-\dfrac{1}{2}=4 \dfrac{3}{10}x=453​+51​−21​=4103​
c) 2 x-x=\dfrac{3}{5}+\dfrac{4}{7}2x−x=53​+74​
x=\dfrac{41}{35}x=3541​
d) x=3 \dfrac{1}{2}-\dfrac{5}{7}+\dfrac{1}{13}-0.25x=321​−75​+131​−0.25
x=2 \dfrac{223}{364}x=2364223​
 

\(a)\left(\dfrac{1}{2}+1,5\right)x=\dfrac{1}{5}\)

\(\Rightarrow2x=\dfrac{1}{5}\)

\(\Rightarrow x=\dfrac{1}{10}\)

\(b)\left(-1\dfrac{3}{5}+x\right):\dfrac{12}{13}=2\dfrac{1}{6}\)

\(\Leftrightarrow-\dfrac{8}{5}+x=\dfrac{13}{6}.\dfrac{12}{13}\)

\(\Leftrightarrow-\dfrac{8}{5}+x=2\)

\(\Leftrightarrow x=\dfrac{18}{5}\)

\(c)\left(x:2\dfrac{1}{3}\right).\dfrac{1}{7}=-\dfrac{3}{8}\)

\(\Leftrightarrow x:\dfrac{7}{3}=-\dfrac{3}{8}:\dfrac{1}{7}\)

\(\Leftrightarrow x=-\dfrac{21}{8}.\dfrac{7}{3}\)

\(\Leftrightarrow x=-\dfrac{49}{8}\)

\(d)-\dfrac{4}{7}x+\dfrac{7}{5}=\dfrac{1}{8}:\left(-1\dfrac{2}{3}\right)\)

\(\Leftrightarrow-\dfrac{4}{7}x+\dfrac{7}{5}=-\dfrac{3}{40}\)

\(\Leftrightarrow-\dfrac{4}{7}x=-\dfrac{59}{40}\)

\(\Leftrightarrow x=\dfrac{413}{160}\)

a)\left(\dfrac{1}{2}+1,5\right) \cdot x=\dfrac{1}{5}(21​+1,5)⋅x=51​

2 \cdot x=\dfrac{1}{5}2⋅x=51​

x=\dfrac{1}{5}: 2x=51​:2

 x=\dfrac{1}{10} x=101​
b) \left(-1 \dfrac{3}{5}+x\right): \dfrac{12}{13}=2 \dfrac{1}{6}(−153​+x):1312​=261​

-1 \dfrac{3}{5}+x=\dfrac{13}{6} \cdot \dfrac{12}{13}−153​+x=613​⋅1312​
x=2+1 \dfrac{3}{5}x=2+153​

 x=3 \dfrac{3}{5} x=353​
c) \left(x: 2 \dfrac{1}{3}\right) \cdot \dfrac{1}{7}=\dfrac{-3}{8}(x:231​)⋅71​=8−3​

x \cdot \dfrac{3}{7} \cdot \dfrac{1}{7}=\dfrac{-3}{8}x⋅73​⋅71​=8−3​

x=\dfrac{-3}{8}: \dfrac{3}{49}x=8−3​:493​
x=\dfrac{-49}{8}=-6 \dfrac{1}{8}x=8−49​=−681​
d) \dfrac{-4}{7} \cdot x+\dfrac{7}{5}=\dfrac{1}{8}:\left(-1 \dfrac{2}{3}\right)7−4​⋅x+57​=81​:(−132​)

\dfrac{-4}{7} x+\dfrac{7}{5}=\dfrac{1}{8} \cdot \dfrac{-3}{5}7−4​x+57​=81​⋅5−3​
-\dfrac{4}{7} x=\dfrac{-3}{40}-\dfrac{7}{5} \\ x=\dfrac{-59}{40}: \dfrac{-4}{7}=\dfrac{413}{160}=2 \dfrac{93}{160}−74​x=40−3​−57​x=40−59​:7−4​=160413​=216093​
 

a) $A=\left[\frac{2}{7}\left(\frac{1}{4}-\frac{1}{3}\right)\right]:\left[\frac{2}{7}\left(\frac{1}{3}-\frac{2}{5}\right)\right]=\left(\frac{1}{4}-\frac{1}{3}\right):\left(\frac{1}{3}-\frac{2}{5}\right)=1\frac{1}{4}$.
b) $B=\frac{\frac{3}{4}\left(\frac{1}{5}-\frac{2}{7}-\frac{1}{3}+\frac{2}{7}\right)}{\frac{1}{5}\left(\frac{2}{7}+\frac{1}{3}\right)-\frac{1}{3}\left(\frac{2}{7}+\frac{1}{3}\right)}=\frac{\frac{3}{4}\left(\frac{1}{5}-\frac{1}{3}\right)}{\left(\frac{1}{5}-\frac{1}{3}\right)\left(\frac{2}{7}+\frac{1}{3}\right)}=1\frac{11}{52}$.

a) \mathrm{A}=\left[\dfrac{2}{7}\left(\dfrac{1}{4}-\dfrac{1}{3}\right)\right]:\left[\dfrac{2}{7}\left(\dfrac{1}{3}-\dfrac{2}{5}\right)\right]=\left(\dfrac{1}{4}-\dfrac{1}{3}\right):\left(\dfrac{1}{3}-\dfrac{2}{5}\right)=1 \dfrac{1}{4}A=[72​(41​−31​)]:[72​(31​−52​)]=(41​−31​):(31​−52​)=141​.
b) \mathrm{B}=\dfrac{\dfrac{3}{4}\left(\dfrac{1}{5}-\dfrac{2}{7}-\dfrac{1}{3}+\dfrac{2}{7}\right)}{\dfrac{1}{5}\left(\dfrac{2}{7}+\dfrac{1}{3}\right)-\dfrac{1}{3}\left(\dfrac{2}{7}+\dfrac{1}{3}\right)}=\dfrac{\dfrac{3}{4}\left(\dfrac{1}{5}-\dfrac{1}{3}\right)}{\left(\dfrac{1}{5}-\dfrac{1}{3}\right)\left(\dfrac{2}{7}+\dfrac{1}{3}\right)}=1 \dfrac{11}{52}B=51​(72​+31​)−31​(72​+31​)43​(51​−72​−31​+72​)​=(51​−31​)(72​+31​)43​(51​−31​)​=15211​