\(\left(-\frac{x}{5}+\frac{2}{3}\right):\frac{11}{5}=\frac{5}{21}+\frac{3}{7}\)

\(-\frac{x}{5}+\frac{2}{3}=\frac{68}{77}\times\frac{11}{5}\)

\(-\frac{x}{5}=\frac{68}{35}-\frac{2}{3}\)

\(-\frac{x}{5}=\frac{134}{105}\)

=>105(-x)=134*5

=>-105x=670

=>x=\(-\frac{134}{21}\)

a: \(=\dfrac{7}{5}\cdot\dfrac{15}{49}-\dfrac{12+10}{15}:\dfrac{11}{5}\)

\(=\dfrac{3}{7}-\dfrac{22}{15}\cdot\dfrac{5}{11}=\dfrac{3}{7}-\dfrac{2}{3}=\dfrac{9-14}{21}=\dfrac{-5}{21}\)

b: =>2,8x-32=-60

=>2,8x=-28

hay x=-10

\(1,4x\frac{15}{49}-\left(\frac{4}{5}+\frac{2}{3}\right):2\frac{1}{5}\)

\(=\frac{3}{7}-\frac{22}{15}:2\frac{1}{5}\)

\(=\frac{3}{7}-\frac{2}{3}=-\frac{5}{21}\)

học tốt ~~~

\(1,4\times\frac{15}{49}-\left(\frac{4}{5}+\frac{2}{3}\right)\div2\frac{1}{5}\)

\(=\frac{14}{10}\times\frac{15}{49}-\frac{22}{15}\div\frac{11}{5}\)

\(=\frac{7}{5}\times\frac{15}{49}-\frac{22\times5}{15\times11}\)

\(=\frac{7\times15}{5\times49}-\frac{22\times5}{15\times11}\)

\(=\frac{7\times7\times3\times5}{5\times7\times7}-\frac{11\times2\times5}{3\times5\times11}\)

\(=3-\frac{2}{3}\)

\(=\frac{7}{3}\)

Giải:

B=1,4 .15/49 - (4/5+2/3) :2 1/5

B=7/5.15/49 - 22/15 : 11/5

B=3/7 - 2/3

B=-5/21

Chúc bạn học tốt!

(x/-5+2/3);11/5-1,4.15/49=|-5|/21

(x/-5+2/3);11/5-1,4.15/49=5/21

(x/-5+2/3);11/5-21/49=5/21

(x/-5+2/3);11/5=5/21+21/49

(x/-5+2/3);11/5=35/147+63/147

(x/-5+2/3);11/5=35+63/147

(x/-5+2/3);11/5=98/147

x/-5+2/3=98/147.11/5

x/-5+2/3=98.11/147.5

x/-5+2/3=1078/735

x/-5+2/3=154/105

x/-5=154/105-2/3

x/-5=154/105-70/105

x/-5=154-70/105

x/-5=84/105

x/-5=-4/-5

suy ra x=-4

* la dau gi vay ban

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