# Math Help - Right track?

1. ## Right track?

980=75(1-75e^(-.07t) find t
Do I divide 75 from each side to give me
980/75=1-75e^(.07t)

How do I bring the 1-75 to the other side now. The book I have on explaining this sucks big time.

Any clue?

Ok I came up with something?
now I divide both sides by 1-75 which gives me
(980/75)/1-75 = e^ -.07t
Then I multiply both sides by Ln which gives me
ln(980/75)/(1-75) = -.07t
then just divide again by -0.07 to isolate t.

Now if it makes sense not sure.

I got an answer of 0.9252???

980=75(1-75e^(-.07t) find t
Do I divide 75 from each side to give me
980/75=1-75e^(.07t)

How do I bring the 1-75 to the other side now. The book I have on explaining this sucks big time.

Any clue?
$980=75\left(1-75e^{-.07t}\right)$

$\frac{980}{75}=1-75e^{-.07t}$

$\frac{980}{75}-1=-75e^{-.07t}$

$\frac{\frac{980}{75}-1}{-75}=e^{-.07t}$

Now since $\frac{\frac{980}{75}-1}{-75}<0$, and $e^{-.07t}>0$ for all values of $t$. We conclude that there is no solution.

3. Awesome pic of the cat.
Ok so on line 4, this is where you apply Ln to each side, and being the left side is negative, you can get a number for it. Ln or Log can never be negative numbers before using the function then???