Question

Solve the following exponential equations. 10^(x+1) − 10^(x−1) = 1287

Answer 1

Answer:x=2.114

Step-by-step explanation:

Given

$10^{x+1}-10^{x-1}=1287$

$10\times 10^x-\frac{10^x}{10}=1287$

Let $10^x=y$

$10y-\frac{y}{10}=1287$

$\frac{100y-y}{10}=1287$

$99y=1287\times 10$

$y=\frac{12870}{99}=130$

$10^x=130$

Taking $\log$both sides

$x\log (10)=\log (130)$

$x=\frac{\log (130)}{1}$

$x=2.114$