Answer: 
Step-by-step explanation:
Given logarithm expression

We need to write it as a single logarithm expression.
First we need to apply exponent rule of logs to remove 7 and 6 in front of logs.

.
Now, we need to apply product rule of logs
.

Therefore, final answer is 
Answer:
x = 60
Step-by-step explanation:
The tip of the triangle's angle is 100 (b/c 180-80)
x + 100 + 20 = 180
x + 120 = 180
x = 60
Answer:
D
Step-by-step explanation:
Answer:
13
Step-by-step explanation:
Replace the variable x with -2 in the expression.
f (-2) = -3 x -2 -2
Simplify (-3 x -2 -2) + 9
Multiply -3 by -2
6 - 2 + 9
Subtract 2 from 6
4 + 9
add 4 and 9
13.