Answer:
y = 
x²
Step-by-step explanation:
Given that y and x² are directly proportional then the equation relating them is
y = kx² ← k is the constant of proportion
When x = 2
y = k × 2² = 4k
When x = 5
y = k × 5² = 25k
Then
25k - 4k = 20 ( difference between values is 20 )
21k = 20 ( divide both sides by 21 )
k =
y = x² ← equation of proportion
Answer:
True because 1/2 an hour is 30 minutes.
Step-by-step explanation:
Answer:
y'(t) = k(700,000-y(t)) k>0 is the constant of proportionality
y(0) =0
Step-by-step explanation:
(a.) Formulate a differential equation and initial condition for y(t) = the number of people who have heard the news t days after it has happened.
If we suppose that news spreads through a city of fixed size of 700,000 people at a time rate proportional to the number of people who have not heard the news that means
<em>dy/dt = k(700,000-y(t)) </em>where k is some constant of proportionality.
Since no one has heard the news at first, we have
<em>y(0) = 0 (initial condition)
</em>
We can then state the initial value problem as
y'(t) = k(700,000-y(t))
y(0) =0
Answer:
24-21
Step-by-step explanation:
2×12=24 7×3=21 I started from 2×2 towards 2×12 when I got the answer and I started 7×1 towards 7×3
