To evaluate a function at a given input, you have to substitute every occurrence of the variable with that particular value.
So, for the first function, you have

The name of the variable is obviously irrelelvant, so the same goes for the second function:

Answer:
60 and 40 or 120 and 20
Step-by-step explanation:
60 x 2=120
40 x 3=120
60 x 40=2400
120 x 1=120
20 x 6=120
120 x 20=2400
You can try a few others, but no others have an lcm of 120
The area of a circle is given by

We can solve this equation for r: divide both sides by pi:

Consider the (positive) square root of both sides:

So, in your case, we have

Answer:
.0625 or A
Step-by-step explanation:
You have to work out the mean. (The simple average of those numbers) Then for each number subtract the Mean and square the result. Then work out the average of those squared differences.