Answer:
40/9
Step-by-step explanation:
Use the work formula,
+
=
, where A is the amount of time it takes one person, B is the amount of time it takes another person, and T is the time it takes for them to work together.
Plug in the times for David and Alex alone:
+
= 
Find the least common denominator, which is 40.
+
= 
= 
Cross multiply and solve for T:
9T = 40
T = 40/9
So, if they worked together, it would take them 40/9 hours
Answer:
a
Step-by-step explanation:
answer
(x+7)^2 + (y-4)^2 = 64
set up equation
the equation of a circle is (x - h)^2 + (y - k)^2 = r^2
where h is the center x coordinate and k is the center y coordinate
values
from the point (-7,4) we know that h = -7 and k = 4
since the radius is 8, r^2 = 8^2 = 64
plug in values
now that we have all the values, we plug them into (x - h)^2 + (y - k)^2 = r^2
(x - h)^2 + (y - k)^2 = r^2
(x - (-7))^2 + (y-4)^2 = 64
(x+7)^2 + (y-4)^2 = 64
The correct answer is:
B: 48
Hope this helped!