Let t be time and r be rate, then if time varies inversely with the rate, the equation is

. If it takes 5 hours to drive a fixed distance at a rate of 80, we can sub those values in to solve for the constant of variation, k.

. Solve for k by multiplying 5 and 80 to get that k = 400. Now let's find a new time t when r is a rate of 70. We will use that k value to do this:

and find that it will take 20 hours to drive the distance at 70 mph when it takes 5 hours to drive the distance at 80 mph. Makes sense that it takes longer to drive a fixed distance when you are going slower.
Answer:
(x + 3)² - 12
Step-by-step explanation:
x²+6x-3
= x²+ 6x + 9 - 12
= (x + 3)² - 12
Answer:-282
Step-by-step explanation:
I hope this helps :)
Answer:
-20c^2 d^3 - 16cd^2
Step-by-step explanation:
Answer:
Measure the diagonals, they should be 5 feet (3,4,5 triangle).
Step-by-step explanation:
As a more general answer, the diagonal measurements of ANY rectangle will be equal. You can calculate the correct measurement using A^2 + B^2 = C^2. A and B are the lengths of the sides and C is the length of the diagonals.