Step-by-step explanation:
Let's say b is the rate of the boat in still water, and c is the rate of the current.
Distance = rate × time
Going upstream:
100 = (b − c) (5)
20 = b − c
Going downstream:
100 = (b + c) (2)
50 = b + c
Solve the system of equations using substitution or elimination. Using elimination, add the equations together:
70 = 2b
b = 35
c = 15
The boat's speed is 35 km/h, and the current's speed is 15 km/h.
Answer:
Second option
Third option
Fourth option
Step-by-step explanation:
We have the following quadratic function

Use the distributive property to multiply the expression


For a function of the form
the x coordinate of the vertex is:

Then in this case the coordinate of the vertex is:


To obtain the y coordinate of the vertex we evaluate the function at 



Then the vertex is: (-3, -16)
We can see in the graph that the zeros of the function are x=1 and x=-7
Then the function is decreasing from -∞ to -3 and then it is increasing from -3 to ∞
The function is positive for
and 
The correct answers are:
Second option
Third option
Fourth option
Never because I had this question and saw it on khan
Answer:
Family a because it is more chronological
Step-by-step explanation:
Answer: Qualquer temperatura menor que -3,4°C. Ou seja, -3,5 ; -3,6 ; ...
Step-by-step explanation: