Me with the following questions. in

Step-by-step explanation:

Eight

590 = 1800 e^(-0.4t)     Divide by 1800

0.32778 = e^(-0.4t)       Put the value for e in the denominator.

0.32778 = 1 / e^(0.4t)   Notice the sign's gone. Multiply both sides by e^(0.4t)

0.32778 *e^(0.4t) = 1    Divide by 0.32778

e^(0.4t) = 3.0508          Take the natural log of both sides.

0.4t = 1.11542                 Divide both sides by 0.4

t = 2.78855

You should put this in the original equation to see if it checks. It does.

Nine

3^(3 - 3x) + 6 = 42         Subtract 6 from both sides

3^(3 - 3x) = 36               Take the log of both sides.

(3 - 3x) ln(3) = ln 36

(3 - 3x) *1.098612 = 3.58352   Divide by 1.098612

3 - 3x = 3.26186             Subtract 3 from both sides

- 3x = 0.26186                 Divide by - 3

x = - 0.087287