235-(-12)=247; his elevation changed by 247 m.
Step-by-step explanation:
The derivative of log is

You can easily derive this using the Change of base rule, and natural log rules

Next, we differentiate with respect to x.


So back to the topic at hand,.
a=7, so we get

We plug in 0, we would get undefined
The answer to your question is 14
I believe both are 119 degrees
36-4.5x+36=102-7.5x-60
72-4.5x=42-7.5x
72+3.5x=42
3.5x=-30
x=8.57