\(a,x+\dfrac{3}{7}=\dfrac{2}{5}+\dfrac{3}{10}\)

\(x+\dfrac{3}{7}=\dfrac{4}{10}+\dfrac{3}{10}\)

\(x+\dfrac{3}{7}=\dfrac{7}{10}\)

\(x=\dfrac{7}{10}-\dfrac{3}{7}\)

\(x=\dfrac{49}{70}-\dfrac{30}{70}\)

\(x=\dfrac{19}{70}\)

\(b,\dfrac{19}{20}-x=\dfrac{8}{5}-\dfrac{3}{4}\)

\(\dfrac{19}{20}-x=\dfrac{32}{20}-\dfrac{15}{20}\)

\(\dfrac{19}{20}-x=\dfrac{17}{20}\)

\(x=\dfrac{19}{20}-\dfrac{17}{20}\)

\(x=\dfrac{2}{20}\)

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

#Urushi☕

a: \(0,25x:3=\frac56\)

=>\(\frac14x=\frac56\cdot3=\frac52\)

=>\(x=\frac52:\frac14=\frac52\cdot4=10\)

b: \(-\frac25x=\left(-\frac25\right)^3\)

=>\(x=\left(-\frac25\right)^3:\left(-\frac25\right)=\left(-\frac25\right)^2=\frac{4}{25}\)

nè

a: Ta có: 

hay x=537,6

b: Ta có: 

hay 

à quên ở đây ko viết phân số đc đừng viết nha

    15 : (-3) + (-7) . (-2) - (-20) : (-5)

=     (-5)     +      14      -         4

=               9                 -         4

=                                 5

\(\text{15:(-3)+(-7).(-2)-(-20):(-5)}\)

\(=-5+14-4\)

\(=9-4\)

= 5 

A) \(\frac{1}{2}\cdot\left(\frac{2}{9}+\frac{3}{7}-\frac{5}{27}\right)\) 

\(=\frac{1}{2}\cdot\frac{1}{2}\)

\(=\frac{1}{4}\)

B)   \(\left(\frac{-5}{28}+1.75+\frac{8}{35}\right):\left(-3\frac{9}{20}\right)\)

\(=\left(\frac{-5}{28}+\frac{7}{4}+\frac{8}{35}\right):\frac{-69}{20}\)

\(=\frac{14}{5}:\frac{-69}{20}\)

\(=\frac{-56}{69}\)

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

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

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

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

Mình thiều nhé thêm :Viết theo thứ tự từ bé đến lớn là :

1/5,3/5,6/5,8/5,20/50

(-6) + (-5) + (-4) + (-3) + (-2)

= [(-6) + (-4)] + [(-5) + (-3) + (-2)]

= (-10) + (-10)

= (-20)

P/s: Cái bước thứ 3 bạn ghi kết quả ra luôn giống như ở trên mình làm đó, không cần phải dài dòng nhé!

Chúc bạn học tốt!! ^^

Ta có: \(\left(-6\right)+\left(-5\right)+\left(-4\right)+\left(-3\right)+\left(-2\right)\)

\(=-\left(2+3+4+5+6\right)\)

=-20