For this case what we must do is use the law of cosines.
We then have the following equation:

Where,
a, b: sides of the triangle
x: angle between sides a and b.
Substituting values we have:

Clearing the value of c we have:
Answer:
An expression that is equivalent to how many feet the oak trees are from each other is:
171 minutes
Explanation:
6 is the initial cost, .08 is the cost per minute and 19.68 is the total, set up an equation that looks like this: (x is the unknown variable)
6+.08x=19.68
19.68-6=13.68
.08x=13.68
.08x/.08=x
13.68/.08=171
x=171
Answer:
the expression is -5 + 2. the sum is -3.
Step-by-step explanation:
First you distributive property:
3x-15=9
Add 15
3x=24
Divide
x=8
I believe D. 180. I am sorry if I am wrong though