\(\frac{459}{460}\)và \(\frac{929}{930}\)

Ta có : \(1-\frac{459}{460}=\frac{1}{460};1-\frac{929}{930}=\frac{1}{930}\)

Vì \(\frac{1}{460}>\frac{1}{930}\)nên \(\frac{459}{460}< \frac{929}{930}\).

Chúc bạn hok tốt !

So sánh:

\(\frac{459}{460} v\text{à} \frac{929}{930}\)

Đáp án:

\(\frac{459}{460}< \frac{929}{930}\)

Chúc bạn học tốt

\(\frac{18}{17}\)và \(\frac{17}{15}\)

Ta có : \(\frac{18}{17}=\frac{18\times2}{17\times2}=\frac{36}{34}\)và giữ nguyên phân số \(\frac{17}{15}\).

\(\frac{36}{34}-1=\frac{2}{34};\frac{17}{15}-1=\frac{2}{15}\)

Vì \(\frac{2}{34}< \frac{2}{15}\)nên \(\frac{36}{34}< \frac{17}{15}\)hay \(\frac{18}{17}< \frac{17}{15}\).

Chúc bạn hok tốt !

\(\frac{18}{17}=\frac{17}{17}+\frac{1}{17}=1+\frac{1}{17}\)

\(\frac{17}{15}=\frac{15}{15}+\frac{2}{15}=1+\frac{2}{15}\)

Có:  \(\frac{1}{17}< \frac{1}{15}\)

và      \(1< 2\)

=> \(1.\frac{1}{17}< 2.\frac{1}{15}\)

=> \(\frac{1}{17}< \frac{2}{15}\)

=> \(1+\frac{1}{17}< 1+\frac{2}{15}\)

=> \(\frac{18}{17}< \frac{17}{15}\)

13-|x+2|=9

=> | x+2|= 13-9=4

=> x+2 = +4/-4

TH1: x+2=4

=> x=4-2=2

TH2: x+2=-4

=> x=-4-2=-6

Vậy x=2/-6

Chúc bạn Hk tốt!!!!!

12-x+2=9

x=5

3 . [ 25 - ( x - 10 ) ] - 75 = 0

3 . [ 25 - ( x - 10 ) ] = 75

25 - ( x - 10 ) = 75 : 3

25 - ( x - 10 ) = 25

x - 10 = 25 - 25

x - 10 = 0

x = 0 + 10

x = 10

Vậy x = 10

\(3\cdot\left[25-\left(x-10\right)\right]-75=0\)

\(3\cdot\left[25-\left(x-10\right)\right]=0+75\)

\(3\cdot\left[25-\left(x-10\right)\right]=75\)

\(25-\left(x-10\right)=75:3\)

\(25-\left(x-10\right)=25\)

\(x-10=25-25\)

\(x-10=0\)

\(x=0+10\)

\(x=10\)

9 . ( - 20 ) . 5 . 5

= 9 . [ ( - 20 ) . 5 ] . 5

= 9 . ( - 100 ) . 5

= ( - 900 ) . 5 

= - 4500

\(\left[-20.5\right].\left(9.5\right)=-100.45=-4500\)