The answer is 28 years
At = A0 * e^(-k * t)
At = 12 g
A0 = 15 g
k = 7.9 × 10^-3 = 0.0079
t = ?
12 = 15 * e^(-0.0079 * t)
12/15 = e^(-0.0079 * t)
0.8 = e^(-0.0079 * t)
Logarithm both sides (because ln(e) = 1:
ln(0.8) = ln(e^(-0.0079 * t))
ln(0.8) = (-0.0079 * t) * ln(e)
-0.223 = -0.0079 * t
t = -0.223 / -0.0079
t = 28.23
t ≈ 28 years
Break into 2 equatins to get x's:
2x-6<4 and 2x-6>-4
Solve for x in both:
2x-6<4
2x<10
x<5
2x-6>-4
2x>2
x>1
Graph both inequalities on the same number line:
<---0-----1-----2-----3-----4-----5-----6--->
Answer:
One solution
Step-by-step explanation:
We know there is only one solution because the lines do not have the same slope, nor are they the exact same line.
So we know they must have just one solution.
Best of luck
