giúp mình với

a: =>2x+5=4

=>2x=-1

hay x=-1/2

b: \(\Leftrightarrow\left(3x-4\right)^2\cdot\left[\left(3x-4\right)^2-1\right]=0\)

=>(3x-4)(3x-5)(3x-3)=0

hay \(x\in\left\{1;\dfrac{4}{3};\dfrac{5}{3}\right\}\)

c: \(\Leftrightarrow3^{x+1}=3^{2x}\)

=>2x=x+1

=>x=1

d: \(\Leftrightarrow2^{2x+3}=2^{2x-10}\)

=>2x+3=2x-10

=>0x=-13(vô lý)

\(\left(\frac{3}{5}\right)^x.\left(\frac{625}{81}\right)^3=\frac{243}{3125}\)

=>\(\left(\frac{3}{5}\right)^x.\left(\frac{5}{3}\right)^{12}=\left(\frac{3}{5}\right)^5\)

=>\(\left(\frac{3}{5}\right)^x=\left(\frac{3}{5}\right)^5:\left(\frac{5}{3}\right)^{12}\)

=>\(\left(\frac{3}{5}\right)^x=\left(\frac{3}{5}\right)^{17}\)

=>x=17

\(\left(\frac{3}{5}\right)^x.\left(\frac{625}{81}\right)^3=\frac{243}{3125}\)

\(\Rightarrow\left(\frac{3}{5}\right)^x.\left(\frac{3}{5}\right)^{12}=\left(\frac{3}{5}\right)^5\)

\(\Rightarrow\left(\frac{3}{5}\right)^x=\left(\frac{3}{5}\right)^5:\left(\frac{3}{5}\right)^{12}\)

\(\Rightarrow\left(\frac{3}{5}\right)^x=\left(\frac{5}{3}\right)^7\)

\(\Rightarrow x=-7\)

a.(2x +1). (2x+1)=1

Mà chỉ có 1.1=1

Vậy 2x + 1=1

               2x=1-1

               2x=0 

Suy ra: x= 0

Hoàng Khánh Thi thiếu nha.

a) (2x+1)² = \(\left(\pm1\right)^2\)

=> 2x + 1 = 1 hoặc 2x + 1 = -1

=> 2x = 0 hoặc 2x = -2

=> x = 0 hoặc x = -1.

a: \(5^{x}\cdot\left(5^3\right)^2=625\)

=>\(5^{x}=\frac{5^4}{5^6}=5^{-2}\)

=>x=-2

b: \(\left(\frac{12}{15}\right)^{x}=\left(\frac53\right)^{-5}-\left(-\frac35\right)^4\)

=>\(\left(\frac45\right)^{x}=\left(\frac35\right)^5-\left(\frac35\right)^4=\left(\frac35\right)^4\cdot\left(\frac35-1\right)=\left(\frac35\right)^4\cdot\frac{-2}{5}=\frac{-2\cdot3^4}{5^5}\)

=>\(x=\log_{0,8}\left(-2\cdot\frac{3^4}{5^5}\right)\)

c: \(\left(-\frac34\right)^{3x-1}=\frac{256}{81}\)

=>\(\left(-\frac34\right)^{3x-1}=\left(-\frac34\right)^{-4}\)

=>3x-1=-4

=>3x=-3

=>x=-1

d: \(172x^2-7^9:98^3=2^{-3}\)

=>\(172x^2=\frac18+\frac{7^9}{7^6\cdot2^3}=\frac18+\frac{7^3}{2^3}=\frac{1+343}{8}=\frac{344}{8}\)

=>\(x^2=\frac{344}{8}:172=\frac{344}{8\cdot172}=\frac28=\frac14\)

=>\(\left[\begin{array}{l}x=\frac12\\ x=-\frac12\end{array}\right.\)

1. 

a) 2ⁿ : 4 = 16

2ⁿ = 16.4

2ⁿ = 64

2ⁿ = 2⁶

=> n = 6

b) 5ⁿ = 625

5ⁿ = 5⁴

=> n = 4

c) 2ⁿ . 16 = 128

2ⁿ = 128 : 16

2ⁿ = 8

2ⁿ = 2³

=> n = 3

d) 3ⁿ⁺³ = 81

3ⁿ⁺³ = 3⁴

=> n + 3 = 4

=>      n = 4 - 3

=>      n = 1

1. 

a) 2ⁿ : 4 = 16

2ⁿ = 16.4

2ⁿ = 64

2ⁿ = 2⁶

=> n = 6

b) 5ⁿ = 625

5ⁿ = 5⁴

=> n = 4

c) 2ⁿ . 16 = 128

2ⁿ = 128 : 16

2ⁿ = 8

2ⁿ = 2³

=> n = 3

d) 3ⁿ⁺³ = 81

3ⁿ⁺³ = 3⁴

=> n + 3 = 4

=>      n = 4 - 3

=>      n = 1

2.

a) x³ = 64

x³ = 4³

=> x = 4

b) (2x + 1)³ = 27

(2x + 1)³ = 3³

2x + 1 = 3

2x = 3 - 1

2x = 2

=> x = 1

c) x³ = x 

=> x = {0;1}

d) 25 + 5x = 7⁵.7³

25 + 5x = 5764801

        5x = 5764801 - 25

        5x = 5764776

=> không có số tự nhiên x thoản mãn