What is the answer to 9^x-90*3^x+729=0 ?

The answer to 9^x-90*3^x+729=0 is x=4,x=2

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

9^x-90*3^x+729=0

9^{x} - 90 \cdot 3^{x} + 729 = 0

x = 4, x = 2

Solution steps

9^{x} - 90 \cdot 3^{x} + 729 = 0

Apply exponent rules

(3^{x})^{2} - 90 \cdot 3^{x} + 729 = 0

Rewrite the equation with

3^{x} = u

(u)^{2} - 90 u + 729 = 0

Solve

u^{2} - 90 u + 729 = 0 : u = 81, u = 9

u = 81, u = 9

Substitute back

u = 3^{x},

solve for

x

Solve

3^{x} = 81 : x = 4

Solve

3^{x} = 9 : x = 2

x = 4, x = 2

5 e^{x} = 1

x, 3^{x} = 10

1 2^{x - 8} = 18

\frac{e ^{2 x + 3}}{e ^{3}} = 5

2 e^{- x} = 3

What is the answer to 9^x-90*3^x+729=0 ?
The answer to 9^x-90*3^x+729=0 is x=4,x=2
Solve for x: 9^x-90*3^x+729=0
The solution is x=4,x=2