(5x-2⁴).7³=2.7⁴

5x-16=2.(7⁴:7³)

5x-16=2.7

5x-16=14

5x=14+16

5x=30

x=30:5=6

14 ⁴ : 2 ³ : 7 ⁴

= 38416 : 8 : 2401

= 4802 : 2401

= 2

14^a=38416

2^3=8

7^4=2401

còn cách nào ko các bn ?

S = 1 + 2 + 2² + 2³ + 2⁴ + 2⁵ + 2⁶ + 2⁷

= (1 + 2) + (2² + 2³) + (2⁴ + 2⁵) + (2⁶ + 2⁷)

= (1 + 2) + 2²(1 + 2) + 2⁴(1 + 2) + 2⁶(1 + 2)

= (1 + 2)(1 + 2² + 2⁴ + 2⁶) 

= 3(1 + 2² + 2⁴ + 2⁶) \(⋮3\)(ĐPCM)

2S = 1 + 2 + 2² + 2³ + 2⁴ + 2⁵ + 2⁶ + 2⁷ 

S = (1+2 ) + (2² + 2³ ) + (2⁴ + 2⁵ ) + (2⁶ +2⁷)

S = 3 + 2²(1+2) + 2⁴(1+2) + 2⁶(1+2)

S = 3+2².3 + 2⁴.3 + 2⁶ .3 

S = 3(1+2² + 2⁴ + 2⁶ ) \(⋮\) 3

=> đpcm

Vì 1+2=3 \(⋮\)3 =>(1+2)+2²+2³+2⁴+2⁵+2⁶+2⁷=>S \(⋮\)3

Vậy S \(⋮\)9

Nhớ k cho mình nhé !

\(\left(6x-3^3\right).5^3=3.5^4\)

\(\Rightarrow\left(6x-27\right)=3\left(5^4\div5^3\right)\)

\(\Rightarrow\left(6x-27\right)=3.5\)

\(\Rightarrow6x-27=15\)

\(\Rightarrow6x=42\)

\(\Rightarrow x=7\)

1)Tính:

a)\(4^2\cdot2=\left(2^2\right)^2\cdot2=2^4\cdot2=2^5=32\)

b)\(36^2:6^2=\left(36:6\right)^2=6^2=48\)

c)\(\left(\frac{2}{5}\right)^{10}:\left(\frac{4}{25}\right)^2=\left(\frac{2}{5}\right)^{10}\cdot\left(\frac{25}{4}\right)^2=\)\(\left(1\right)^{10}\cdot\left(\frac{5}{2}\right)^2=1\cdot\frac{5^2}{2^2}=1\cdot\frac{25}{4}=\frac{25}{4}\)

a

\(4^2.2=16.2=32\)

b\(36^2:6^2=36.36:6.6=36.36:36=36\)

c

3)

a)\(x:\left(-\frac{1}{3}\right)^5=\left(-\frac{1}{3}\right)^3\)

                      \(x=\left(-\frac{1}{3}\right)^3\cdot\left(-\frac{1}{3}\right)^5\)           

                      \(x=\left(-\frac{1}{3}\right)^8\)

b)\(\left(\frac{2}{3}\right)^{16}\cdot x=\left(\frac{2}{3}\right)^{18}\)

                      \(x=\left(\frac{2}{3}\right)^{18}:\left(\frac{2}{3}\right)^{16}\)

                      \(x=\left(\frac{2}{3}\right)^2\)

                      \(x=\frac{2^2}{3^2}\)

                      \(x=\frac{4}{9}\)

=49-9+200=240

=49-9+200=240

\(324-\left\{38+\left[7\cdot3-24:6+\left(9-7\right)^3\right]\right\}:15\)

\(=324-\left\{38+21-4+2^3\right\}:15\)

\(=324-\left\{38+17+8\right\}:15\)

\(=324-\dfrac{63}{15}=324-4,2=319,8\)