chỗ \(\dfrac{3}{5}\) là \(\left|\dfrac{-3}{5}\right|\)

1: \(=5.7\left(-6.5-3.5\right)=-10\cdot5.7=-57\)

a) (\(2+\dfrac{4}{5}-\dfrac{7}{12}\)

bn tính máy tính cũng ra mà

a: \(=9-\dfrac{1}{8}-1=8-\dfrac{1}{8}=\dfrac{63}{8}\)

b: \(=2.25+0.4\cdot0.3-\left(-\dfrac{3}{5}\right)^2\)

\(=3.45-0.36=3.09\)

Nàng tiên cá

a) \(\left(2+\frac{4}{5}-\frac{7}{12}\right).\left(\frac{6}{7}-\frac{2}{5}\right)^2\)

\(=\left(\frac{120}{60}+\frac{48}{60}-\frac{70}{60}\right).\left(\frac{36}{49}-2.\frac{6}{7}.\frac{2}{5}+\frac{4}{25}\right)\)

\(=\frac{98}{60}.\left(\frac{36}{49}-\frac{24}{35}+\frac{4}{25}\right)\)

\(=\frac{49}{30}.\left(\frac{900}{1225}-\frac{840}{1225}+\frac{196}{1225}\right)\)

\(=\frac{49}{30}.\frac{256}{1225}\)

\(=\frac{128}{375}\)

b) \(\left(2\frac{1}{2}+3,5\right):\left(-4\frac{1}{6}+3\frac{1}{7}\right)+7,5\)

\(=\left(\frac{5}{2}+\frac{7}{2}\right):\left(\frac{-25}{6}+\frac{22}{7}\right)+\frac{15}{2}\)

\(=6:\frac{-43}{42}+\frac{15}{2}\)

\(=\frac{-72}{43}+\frac{15}{2}\)

\(=\frac{501}{86}\)

Bài 2: 

a: \(=\dfrac{7}{9}\left(\dfrac{7}{6}-\dfrac{19}{20}-\dfrac{1}{15}\right)+\dfrac{22}{5}\cdot\dfrac{1}{24}\)

\(=\dfrac{7}{9}\cdot\dfrac{3}{20}+\dfrac{22}{120}=\dfrac{7}{60}+\dfrac{11}{60}=\dfrac{18}{60}=\dfrac{3}{10}\)

b: \(=\left(\dfrac{35-32}{60}\right)^2+\dfrac{4}{5}\cdot\dfrac{70-45}{80}\)

\(=\dfrac{1}{400}+\dfrac{4\cdot25}{400}=\dfrac{101}{400}\)

\(\left(\dfrac{7}{8}-\dfrac{3}{4}\right)\cdot\dfrac{1}{3}-\dfrac{2}{7}\cdot\left(3,5\right)^2\)
\(=\left(\dfrac{7}{8}-\dfrac{6}{8}\right)\cdot\dfrac{1}{3}-\dfrac{2}{7}\cdot\dfrac{49}{4}\)
\(=\dfrac{1}{8}\cdot\dfrac{1}{3}-\dfrac{7}{2}\)
\(=\dfrac{1}{24}-\dfrac{7}{2}\)
\(=\dfrac{1}{24}-\dfrac{84}{24}\)
\(=-\dfrac{83}{24}\)
#データネ

`(7/8-3/4)xx1/3-2/7xx(3,5)^2`

`=(7/8-6/8)xx1/3-2/7xx12,25`

`=1/8xx1/3-2/7xx12,25`

`=1/24-7/2`

`=1/24-84/24`

`=-83/24`

làm ơn giúp 🙏🙏🙏

a: =>1/3x+2/5x-2/5=0

=>11/15x-2/5=0

=>11/15x=2/5

=>x=2/5:11/15=2/5*15/11=30/55=6/11

b: =>-5x-1-1/2x+1/3=x

=>-11/2x-2/3-x=0

=>-13/2x=2/3

=>x=-2/3:13/2=-2/3*2/13=-4/39

c: (x+1/2)(2/3-2x)=0

=>x+1/2=0 hoặc 2/3-2x=0

=>x=1/3 hoặc x=-1/2

d: 9(3x+1)^2=16

=>(3x+1)^2=16/9

=>3x+1=4/3 hoặc 3x+1=-4/3

=>3x=1/3 hoặc 3x=-7/3

=>x=1/9 hoặc x=-7/9

a) \(\left(4x-10\right)\left(24+5x\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}4x-10=0\\24+5x=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{10}{4}=\dfrac{5}{2}\\x=-\dfrac{24}{5}\end{matrix}\right.\)

Vậy \(S=\left\{-\dfrac{24}{5};\dfrac{5}{2}\right\}\)

b) \(\left(3.5-7x\right)\left(0.1x+2.3\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}3.5-7x=0\\0.1x+2.3=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{3.5}{7}=\dfrac{1}{2}\\x=-\dfrac{2.3}{0.1}=-23\end{matrix}\right.\)

Vậy \(S=\left\{-23;\dfrac{1}{2}\right\}\)