Question

tìm số nguyên x biết

a, 2/5+-3/7=x/70

b, 5/3+-14/3 < x < 8/5+18/10

Answer 1

a)=-1/35=2/70

=>x=2

vậy x= 2

b)ta chia thành 2 vế

vế 1):5/3+-14/3=-11/3=-55/15

vế 2):8/5+18/10=17/5=51/15

từ 2 vế ta có :-55/15<x<51/15

=>x\(\in\){\(\frac{-54}{15}\),.............,\(\frac{50}{15}\)}

vậy x\(\in\){\(\frac{-54}{15}\),.......,\(\frac{50}{15}\)}

Answer 2

      \(\frac{2}{5}+\left(\frac{-3}{7}\right)=\frac{x}{70}\)                     

=>\(\frac{-1}{35}\)                \(=\frac{x}{70}\)

=>\(\frac{-2}{70}\)                \(=\frac{x}{70}\)

VẬY x = -2

Answer 3

b/      \(\frac{5}{3}+\left(\frac{-14}{3}\right)< x< \frac{8}{5}+\frac{18}{10}\)

      =>                      \(-3< x< \frac{17}{5}\)

    =>                      \(-3< x< 3.4\)

    =>        \(x\left\{-2;-1;0;1;2;3\right\}\)

VẬY ............