All real numbers except -4 and 9.
The domain of an expression is the range of all values for which the expression is defined. Looking at the expression, it will legal everywhere except when a^2 - 5a - 36 is equal to 0. Since that's a quadratic equation, we can use the quadratic formula to find where its value is 0, giving -4 and 9.
Therefore the domain of the expression is, All real numbers except -4 and 9.
Answer:
The reference angle is 
Step-by-step explanation:
The given angle is
The reference angle is the acute angle, that a given angle makes with the x-axis.
First let us make a sketch of the given angle. <em>See diagram in attachment.</em>
Let
be the reference angle of 
Then, from the diagram, we need to subtract
from
to get to
.
We can therefore write the following equation and solve for
.

We group like terms to get,

We collect LCM to get,

We simplify to get,

We divide through by 
to get,
The correct answer is D.
The sample is not biased. It is a random sample.