What is the answer to 3^x-3^{x-1}+3^{x-2}=21 ?

The answer to 3^x-3^{x-1}+3^{x-2}=21 is x=3

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

3^x-3^{x-1}+3^{x-2}=21

3^{x} - 3^{x - 1} + 3^{x - 2} = 21

x = 3

Solution steps

3^{x} - 3^{x - 1} + 3^{x - 2} = 21

Factor

3^{x} - 3^{x - 1} + 3^{x - 2} : 7 \cdot 3^{x - 2}

7 \cdot 3^{x - 2} = 21

Divide both sides by

7

3^{x - 2} = 3

Apply exponent rules

x - 2 = 1

Solve

x - 2 = 1 : x = 3

x = 3

e^{(2 t + 1)} = 9 e^{(1 - t)}

x, 2 e^{3 x} = 4 e^{5 x}

5^{x - 3} = 10

x, 2^{x} - 2^{y} = 128

6 = 12 \cdot 5^{- k^{20}}

What is the answer to 3^x-3^{x-1}+3^{x-2}=21 ?
The answer to 3^x-3^{x-1}+3^{x-2}=21 is x=3
Solve for x: 3^x-3^{x-1}+3^{x-2}=21
The solution is x=3