Answer:
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.
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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