Answer:
170
Step-by-step explanation:
Answer:
B. 88.8
Step-by-step explanation:
let x represent class y
(x+71.2)/2=80 multiply each side by 2
x+71.2=160 subtract 71.2 by both sides
x=88.8
or
trial an error
replace x with each of the numbers and see if it plugs in.
example:
(80.5+71.2)/2=80
151.7/2=80
75.85=80?
false. incorrect
another example:
(88.8+71.2)/2=80
160/2=80
80=80?
true. correct
Answer : (0,3) U (3, ∞)
We need to find the interval(s) over which the function is decreasing
We look at the intervals of x where the graph is decreasing
Decreasing interval of the graph is the part where the graph goes down
We look at the part where the graph changes direction
In the middle inverted U shaped graph , the graph changes direction and start decreasing at x=0
the graph is decreasing till x=3
so first decreasing interval is x=0 to 3. we write it as (0,3)
After x=3 the graph starts decreasing and it goes to infinity
So the second decreasing interval is 3 to infinity . We write it as (3, ∞)
Now combine both intervals by a 'U' union
(0,3) U (3, ∞)
