I don't understand life anymore....
Answer:

Step-by-step explanation:
we have

Solve for a
That means ----> Isolate the variable a
Factor 3 in the numerator right side

Simplify right side

subtract a both sides


subtract 1 both sides


Rewrite

Answer:
The circumference would be 12*3.14/2=18.84
Answer:
The domain of the expression is all real numbers except where the expression is undefined. In this case, there is no real number that makes the expression undefined.
(
−
∞
,
∞
)
{x
|
x ∈ R
}
Hope this helps I'm 80% sure this right.