Let this guide you through
Answer:
The equation for the relationship is
.
Step-by-step explanation:
Given that point
is part of a direct relationship. That is:

(1)
Where
is the proportionality constant.
If we know that
and
, then the proportionality constant is:



Lastly, the equation for the relationship is
.
2.50$ is the better deal. If you times 0.70$ to 5 it is 3.5$ which is more expensive
9514 1404 393
Answer:
a) 600
b) see below
c) 1.26 hours
Step-by-step explanation:
a) The value of y when x=0 is the coefficient of the exponential term:
y = 600·3^(-0) = 600·1 = 600
There were 600 atoms to start.
__
b) see attached for a graph
__
c) The graph shows 150 atoms at t = 1.26, about 1.26 hours after the start of time counting.
If you want to find that value algebraically, substitute for y and solve for x. Logarithms are involved.
150 = 600·3^(-x)
150/600 = 3^(-x)
log(1/4) = -x·log(3)
x = -log(1/4)/log(3) = log(4)/log(3) ≈ 1.2618595
After about 1.26 hours, there were 150 atoms.
1). 2x-1>0
2x>1
x>½
2) 21-3y<0
-3y<-21
y>7
3) 5-3c>80
-3c>75
c<-25