20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.201520152015.2016 + 20162016.2015

vế c ,dấu gạch ngang là biểu thị phân số

giúp mình với nào

mik chỉ bit câu b) , c) thôi !!!

b) 20162016.2015 - 20152015.2016

= 2016 . 10001 . 2015 - 2015 . 10001 . 2016

=2016.2015 - 2015.2016

= 0

c) 1

40=2³.5

45=3².5

ƯCLN(40,45)=5

Ta có: 40=2.2.2.5
           45=3.3.5
       ƯCLN(40,45)=2.2.2.5=40

B(40)={0;40;80;120;160;200;240;280;320;360;...}
B(45)={0;45;90;135;180;225;270;315;360;..}
=> BCNN(40,45)=360

 Ta có: 40=2³.5

            45=5.3²

=>BCNN(40;45)Là 2³.9.5=180

Vậy BCNN(40;45)=180

\(a,\dfrac{-3}{5}+\dfrac{7}{21}+\dfrac{-4}{5}+\dfrac{7}{5}\)

\(=\left(\dfrac{-3}{5}+\dfrac{7}{5}\right)+\dfrac{7}{21}+-\dfrac{4}{5}\)

\(=\dfrac{4}{5}+\dfrac{7}{21}+-\dfrac{4}{5}\)

\(=\left(\dfrac{4}{5}+\dfrac{-4}{5}\right)+\dfrac{7}{21}\)

\(=0+\dfrac{7}{21}=\dfrac{7}{21}\)

\(b,\dfrac{-3}{17}+\left(\dfrac{2}{3}+\dfrac{3}{17}\right)\)

\(=-\dfrac{3}{17}+\dfrac{2}{3}+\dfrac{3}{17}\)

\(=\left(\dfrac{-3}{17}+\dfrac{3}{17}\right)+\dfrac{2}{3}\)

\(=0+\dfrac{2}{3}=\dfrac{2}{3}\)

\(c,\dfrac{-5}{21}+\left(\dfrac{-16}{21}+1\right)\)

\(=\dfrac{-5}{21}+\dfrac{-16}{21}+1\)

\(=\dfrac{-21}{21}+1\)

\(=\left(-1\right)+1=0\)

Tick mình nha ^^

a.\(\dfrac{-3}{5}\)+\(\dfrac{7}{21}\)+\(\dfrac{-4}{5}\)+\(\dfrac{7}{5}\)= (\(\dfrac{-3}{5}\)+\(\dfrac{-4}{5}\)+\(\dfrac{7}{5}\)) + \(\dfrac{7}{21}\)=0+\(\dfrac{7}{21}\)=\(\dfrac{7}{21}\)

b.\(\dfrac{-3}{17}\)+(\(\dfrac{2}{3}\)+\(\dfrac{3}{17}\))= \(\dfrac{-3}{17}\)+\(\dfrac{3}{17}\)+\(\dfrac{2}{3}\)=0+\(\dfrac{2}{3}\)=\(\dfrac{2}{3}\)

c.\(\dfrac{-5}{21}\)+(\(\dfrac{-16}{21}\)+1)=\(\dfrac{-5}{21}\)+\(\dfrac{-16}{21}\)+1=(-1)+ 1 = 0

a: \(-\dfrac{3}{5}+\dfrac{7}{21}+\dfrac{-4}{5}+\dfrac{7}{5}=-1+\dfrac{1}{3}+\dfrac{7}{5}=\dfrac{11}{15}\)

b: \(\dfrac{-3}{17}+\left(\dfrac{2}{3}+\dfrac{3}{17}\right)=\dfrac{2}{3}\)

c: \(\dfrac{-5}{21}+\dfrac{-16}{21}+1=-1+1=0\)

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

Nhân cả 2 vế với 15 ,ta được:

\(\frac{15.\left(x-4\right)}{-5}=\frac{15.\left(1-2x\right)}{3}\)

\(\Leftrightarrow\left(-3\right).\left(x-4\right)=5.\left(1-2x\right)\)

\(\Leftrightarrow-3x+12=5-10x\)

\(\Leftrightarrow-3x+10x=5-12\)

\(\Leftrightarrow7x=-7\)

\(\Leftrightarrow x=-1\)

Vậy x=-1

(𝑥−4)/−5=(1−2𝑥)/3

−15⋅𝑥−4−5=−15⋅−2𝑥+13

−15⋅𝑥−4−5=−15⋅−2𝑥+13

3(𝑥−4)=−5(−2𝑥+1)

3(x-4)=-5(-2x+1)

3(𝑥−4)=−5(−2𝑥+1)

3𝑥−12=−5(−2𝑥+1)

3𝑥−12=−5(−2𝑥+1)

3𝑥−12=10𝑥−5

𝑥 = -1