a) (-2)+ (-5) = -7

Vì: -7< -5

=> (-2)+ (-5) < -7

b) (-3)+ (-8)= -11

Vì: (-10) > (-11)

=> -10> (-3)+ (-8)

a)(-2)+(-5)<(-5)

b)(-10)>(-3)+(-8)

ĐS. a) b) ;

c) ; d)

Ta có:

                \(\frac{a}{b}=\frac{a\times\left(b+m\right)}{b\times\left(b+m\right)}=\frac{a\times b+a\times m}{b\times b+b\times m}\)

                \(\frac{a+m}{b+m}=\frac{\left(a+m\right)\times b}{\left(b+m\right)\times b}=\frac{a\times b+m\times b}{b\times b+b\times m}\)

vì \(\frac{a}{b}>1\) nên \(a>b\), ta suy ra \(a\times m>b\times m\)

hay \(a\times b+a\times m>a\times b+m\times b\)

hay \(\frac{a\times b+a\times m}{b\times b+b\times m}>\frac{a\times b+m\times b}{b\times b+b\times m}\)

hay \(\frac{a}{b}>\frac{a+m}{b+m}\)

Vì \(\frac{a}{b}>1\)

=> a > b

=> a.m > b.m

=> a.m + a.b > b.m + a.b

=> a.(b + m) > b.(a + m)

=> \(\frac{a}{b}>\frac{a+m}{b+m}\)

a: Gọi số cần tìm là x

Theo đề, ta có 7/25<x/30<-1/5

mà 7/25>-1/5

nên \(x\in\varnothing\)

b: Gọi hai số cần tìm lần lượt là a,b

Theo đề,ta có: -3>2a>b>-6

\(\Leftrightarrow\left\{{}\begin{matrix}2a=-4\\b=-5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=-2\\b=-5\end{matrix}\right.\)

\(a\)) \(3< 5\)

\(b\)) \(-3>-5\)

\(c\))\(4>-6\)

\(d\)) \(10>-10\)

a) 3 _< 5

b) -3 > -5

c) 4 > -6

d) 10 > -10

Vì \(\frac{-7}{-9}=\frac{7}{9}\)

Nên ô trống là 9

ai tik mik mik tik lại cho

a, Ta có: \(\dfrac{6}{15}-\dfrac{1}{10}=\dfrac{2}{5}-\dfrac{1}{10}=\dfrac{4}{10}-\dfrac{1}{10}=\dfrac{3}{10}< 1\)

\(\Rightarrow\dfrac{6}{15}-\dfrac{1}{10}< 1\)

b, Ta có:\(\dfrac{12}{18}-\dfrac{1}{6}=\dfrac{4}{6}-\dfrac{1}{6}=\dfrac{3}{6}=\dfrac{1}{2}>\dfrac{1}{3}\)

\(\Rightarrow\dfrac{6}{15}-\dfrac{1}{6}>\dfrac{1}{3}\)

2 < 7

-2 > -7

3 > -8

4 > -4

\(2< 7\) \(-2>-7\) \(3>-8\) \(4>-4\)