The goal to proving identities is to transform one side into the other. We can only pick one side to transform while the other side stays the same the entire time. The general rule of thumb is to transform the more complicated side (though there may be exceptions to this guideline).
So I'll take the left hand side and try to turn it into 
One way we can do that is through the following steps:

Since we've shown that the left hand side transforms into the right hand side, this verifies the equation is an identity.
Exponential model because it's increasing rapidly.
Answer:
Step-by-step explanation:
tan47=x/18
x=18tan47
cosCDB=7/x
cosCDB=7/(18tan47)
CDB=arccos(7/(18tan47))
CDB=68.74
What tray..there is not enough information to help you
Answer:
167b + 84
Step-by-step explanation:
Multiplication is indicated between a number and a variable by writing them next to each other. A "product" is the result of multiplication, so "the product of 167 and b" is written 167b.
If you want a value that is 84 more than that, you get it by adding 84.
167b + 84