\(\dfrac{1}{3}\cdot x+\dfrac{2}{5}\cdot\left(x+1\right)=0\)

\(\dfrac{1}{3}\cdot x+\dfrac{2}{5}\cdot x+\dfrac{2}{5}\cdot1\)=0

\(x\cdot\left(\dfrac{1}{3}+\dfrac{2}{5}\right)+\dfrac{2}{5}=0\)

\(x\cdot\dfrac{2}{5}+\dfrac{2}{5}=0\)

\(\dfrac{2}{5}\cdot\left(x+1\right)=0\)

x+1=0

=>x=-1

vậy x=-1

=_=

á mik nhầm:(-4)*25=-100

1-5+9-13+...+393-397

=(-4)+(-4)+...+(-4)

=(-4)*100

=-400

sunny

x=13.6

cấu trúc câu hỏi sai bn nek:>>>>>>

A 

tick mik^^

a/7/15;3/5;2/3

b/17/21;11/14;5/7