2

I try to solve the following equation:

$6^x=36\cdot (9.75)^{x-2}$

I tried:

$1=6\cdot (9.75)^{x-2}$

But this is obviously wrong!

I think it would be smarter to bring the whole expression on one side. How should I proceed instead?

3 Answers3

14

Divide each side by $36$ to get $6^{x-2}=9.75^{x-2}$. Hence $x=2$.

2

Taking log

$x\log 6 = \log 36 + (x-2)\log9.75$

$x(\log6 - \log9.75) = \log36 - 2\log9.75$

$x = \frac{\log36 - 2\log9.75}{\log6 - \log9.75}$

$x = 2\frac{\log6 - \log9.75}{\log6 - \log9.75}$

$x = 2$

user2369284
  • 2,231
2

$$6^x=36\cdot9.75^{x-2}6^x=6^2(9+3/4)^{x-2}$$ $$6^{x-2}=(39/4)^{x-2}$$ $$\left(\frac{6}{39/4}\right)^{x-2}=1$$ $$\left(\frac{24}{39}\right)^{x-2}=\left(\frac{24}{39}\right)^0$$ $$x-2=0$$ $$x=2$$

Adi Dani
  • 16,949