a, \(4320:9-8640:18+750\)

\(=4320:9-(8640:2):(18:2)+750\)

\(=4320:9-4320:9+750\)

\(=(4320-4320):9+750\)

\(=0:9+750=0+750=750\)

a, $4320:9-8640:18+750$

$=4320:9-(8640:2):(18:2)+750$

$=4320:9-4320:9+750$

$=(4320-4320):9+750$

$=0:9+750=0+750=750$

a, 4320 : 9 - 8640 : 18 + 750

     = 4320 : 9 - (8640 : 2) : 9 + 750

    =   4320 : 9 - 4320 : 9  + 750

    = 0 + 750

     = 750

\(\dfrac{23}{5}-x=-\dfrac{1}{6}+\dfrac{1}{2}\)

\(=>\dfrac{23}{5}-x=\dfrac{1}{3}\)

\(=>x=\dfrac{23}{5}-\dfrac{1}{3}\)

\(=>x=\dfrac{64}{15}\)

\(\dfrac{23}{5}-x=-\dfrac{1}{6}+\dfrac{1}{2}\\ =>\dfrac{23}{5}-x=\dfrac{1}{3}\\ =>x=\dfrac{23}{5}-\dfrac{1}{3}\\ =>x=\dfrac{64}{15}\)

Ta có:

\(3^{484}=3^{4.121}=(3^{4})^{121}=81^{121}\)

\(4^{363}=4^{3.121}=(4^{3})^{121}=64^{121}\)

Vì \(81>64=>3^{484}>4^{363}\)

3⁴⁸⁴ = (3⁴)¹²¹ = 81¹²¹

4³⁶³ = (4³)¹²¹ = 64¹²¹

Vì 81 > 64 ⇒ 81¹²¹ > 64¹²¹ ⇒ 3⁴⁸⁴ > 4³⁶³

\((x-3)^{3}=3^{0}+3^{1}+2^{2}.5\)

\(=>(x-3)^{3}=1+3+4.5\)

\(=>(x-3)^{3}=24\)

Vì không có cơ số nào có số mũ là \(3\) mà là \(24\)

Vậy \(x\in\left\{\varnothing\right\}\)

\(1024:64+\left[140:\left(38+\dfrac{2}{5}\right)-\dfrac{1}{3}\right]\\ =16+\left[140:\dfrac{192}{5}-\dfrac{1}{3}\right]\\ =16+\left[\dfrac{175}{48}-\dfrac{1}{3}\right]\\ =16+\dfrac{53}{16}\\ =\dfrac{309}{16}\)

______________________

\(-1,62+\dfrac{2}{5}+x=7\\ =>-\dfrac{61}{50}+x=7\\ =>x=7--\dfrac{61}{50}\\ x=7+\dfrac{61}{50}\\ x=\dfrac{411}{50}\)

-1,62 + \(\dfrac{2}{5}\) + x = 7

                    x = 7 + 1,62 - \(\dfrac{2}{5}\)

                    x = 8,62 - 0,4

                    x = 8,22

           \(\dfrac{9}{5}\) = - 0,15 - x

- 0,15 - x = 1,8

          - x = 1,8 + 0,15

          - x = 1,95

            x = - 1,95

     Vậy ...

`@` `\text {Ans}`

`\downarrow`

\(-\dfrac{3}{5}-x=0,75\)

\(\Rightarrow x=-\dfrac{3}{5}-0,75\)

\(\Rightarrow x=-\dfrac{27}{20}\)

Vậy, `x = `\(-\dfrac{27}{20}\)

a, 40= 2³ x 5

60 = 2² x 3 x 5 

ƯCLN(40;60)= 2² x 5 = 20

b, 28 = 2² x 7

39 = 3 x 13

35 = 5 x 7

ƯCLN(28;39;35)=1

c, 48 = 2⁴ x 3

60 = 2² x 3 x 5

120 = 2³ x 3 x 5

ƯCLN(48;60;120)= 2² x 3 = 12

d, 30 = 2 x 3 x 5

75 = 3 x 5²

135= 3³ x 5

Vậy ƯCLN(30;75;135)= 3 x 5 = 15