Answer:
Step-by-step explanation:
let the speed of one plane=x mph
speed of other plane=x+120 mph
x×1.5+(x+120)×1.5=1620
(x+x+120)×1.5=1620
(2x+120)×1.5=1620
3x+180=1620
3x=1620-180
3x=1440
x=480
speed of one plane=480 mph
speed of second plane=480+120=600 mph
Answer:
B.
Step-by-step explanation:
Use the multiplication table of 12 and find that 5x12=60. Answer B is the only one that has that.
Answer:
lol
Step-by-step explanation:
Answer:
-2/3
Step-by-step explanation:
down 2, right 3
Answer:
Critical points:
and 
Step-by-step explanation:
First, the function, which is a division of two functions, has to be derived:
, where
and
.
The derivatives of each function are, respectively:


All components are replaced and expressed is simplified afterwards:
![f'(x) = \frac{(x^{3})\cdot (-5)-(3\cdot x^{2})\cdot [5\cdot (8-x)]}{25}](https://tex.z-dn.net/?f=f%27%28x%29%20%3D%20%5Cfrac%7B%28x%5E%7B3%7D%29%5Ccdot%20%28-5%29-%283%5Ccdot%20x%5E%7B2%7D%29%5Ccdot%20%5B5%5Ccdot%20%288-x%29%5D%7D%7B25%7D)




Let
be equalized to zero and critical numbers are found by the First Derivative Test:

The critical points are:
and 