You didn’t put your whole question so I can’t help sorry :(((((((((((
Answer:

Step-by-step explanation:
By definition, we can write ln instead of log. WHEN??
Whenever the base of the logarithm is the number "e".
Hence, when we have:

We can write it in shortcut as:

Hence, ln x can also be written as 
Fourth answer choice is right.
Answer:
8 cm
Step-by-step explanation:
f(x) = x^2 + 6x - 7
y = x^2 + 6x - 7
y = (x - 1)(x + 7)
x + 7 = 0
x = -7
x - 1 = 0
x = 1
The x-intercepts are -7 and 1.
Since the leading coefficient is a positive, the graph will point upwards.
So, the graph of the function is D.
Time for first plane = 625 / 250
= 2.5 hours
after 1.25 hours
boeing 747 takes 1.25 hours (2.5 - 1.25) to arrive at the same location at the same time
so, speed = distance / time
= 625 / 1.25
= 500
the average speed of the boeing 747 is 500 mph