<

=

\(\dfrac{4}{7}\) = \(\dfrac{8}{14}\) < \(\dfrac{9}{14}\) 

<    =

spam rồi, vừa hỏi câu này xong

a. <

b. =

a)4/7 < 9/14

b)8/12 = 10/15

a)\(\dfrac{-8}{9}< \dfrac{-7}{9}\\ \dfrac{6}{7}< \dfrac{11}{10}\)

a) Vì -8<-7 nên \(\dfrac{-8}{9}< \dfrac{-7}{9}\)

b) Ta có: \(\dfrac{6}{7}< 1;\dfrac{11}{10}>1\)

nên \(\dfrac{6}{7}< \dfrac{11}{10}\)

Giải:

a) -8/9 < -7/9

b) Ta có: 6/7 = 60/70

                 11/10 = 77/70

Vì 60/70 < 77/70 nên :

    6/7 < 11/10

a: căn 14<4

=>7+căn 14<4+7=11

b: -căn 5<-2

=>-căn 5+9<-2+9=7

d: \(\sqrt{145}< 13\)
=>-11+căn 145<-11+13=2

e: \(7-4\sqrt{5}+2=9-4\sqrt{5}>0\)

=>7-4căn 5>-2

f: -4căn 5>-9

=>-9-4căn 5>-9-9=-18

a)

Ta có: \(BCNN\left( {10,15} \right) = 30\) nên

\(\begin{array}{l}\dfrac{7}{{10}} = \dfrac{{7.3}}{{10.3}} = \dfrac{{21}}{{30}}\\\dfrac{{11}}{{15}} = \dfrac{{11.2}}{{15.2}} = \dfrac{{22}}{{30}}\end{array}\)

Vì \(21 < 22\) nên \(\dfrac{{21}}{{30}} < \dfrac{{22}}{{30}}\) do đó \(\dfrac{7}{{10}} < \dfrac{{11}}{{15}}\).

b)

Ta có: \(BCNN\left( {8,24} \right) = 24\) nên

\(\dfrac{{ - 1}}{8} = \dfrac{{ - 1.3}}{{8.3}} = \dfrac{{ - 3}}{{24}}\)

Vì \( - 3 >  - 5\) nên \(\dfrac{{ - 3}}{{24}} > \dfrac{{ - 5}}{{24}}\) do đó \(\dfrac{{ - 1}}{8} > \dfrac{{ - 5}}{{24}}\).

a: 7/8>210/243

b: 11/15<13/14

c: 31/41<313/413

d: 18/53<26/78

- 3/4 < 4/3 (vì 3/4 < 1 < 4/3 nên 3/4 < 4/3).

- 10/7 > 7/9 (vì 10/7 > 1 > 7/9 nên 10/7 > 7/9).

- 12/11 > 11/10 (vì 12/11 > 1 > 11/10 nên 12/11 > 11/10).

3/4 < 4/3 vi 3/4 be hon 1con 4/3 lon hon 1

10/7 > 7/9 vi 10/7 lon hon 1 con 7/9 be hon 1

12/11 > 11/10 vi 12/11 lon hon 1 con 11/10 be hon 1

5 phần = 5 = \(\dfrac{5}{} \) :>

b

\(a,2003\cdot2005=\left(2004-1\right)\left(2004+1\right)=2004^2-1< 2004^2\)

\(b,7^{16}-1\\ =\left(7^8-1\right)\left(7^8+1\right)=\left(7^4-1\right)\left(7^4+1\right)\left(7^8+1\right)\\ =\left(7^2-1\right)\left(7^2+1\right)\left(7^4+1\right)\left(7^8+1\right)\\ =\left(7-1\right)\left(7+1\right)\left(7^2+1\right)\left(7^4+1\right)\left(7^8+1\right)\\ =48\left(7^2+1\right)\left(7^4+1\right)\left(7^8+1\right)>8\left(7^2+1\right)\left(7^4+1\right)\left(7^8+1\right)\)

a. Dựa vào tính chất thừa và thiếu, suy ra: 2003 . 2005 = 2004²