Answer:
She's been charged 84 dollars
Step-by-step explanation:
Let's call each month m
if every month it deducts 7 dollars, then to find how much has been charged after a year, we do
-7 * 12 = -84
Answer:
d
Step-by-step explanation:
Answer:
$68.52
Step-by-step explanation:
$3.57 Is the tax he pays
Answer:
The value of x at this instant is 3.
Step-by-step explanation:
Let
, we get an additional equation by implicit differentiation:
(1)
From the first equation we find that:
(2)
By applying (2) in (1), we get the resulting expression:
(3)

If we know that
and
, then the first derivative of x in time is:

From (1) we determine the value of x at this instant:




The value of x at this instant is 3.