Answer:
m = -5, 0
Step-by-step explanation:
Easiest and quickest way to do this is to graph the equation and find where it intersects the x-axis. If not, then use completing the square or quadratic formula to find your roots.
Answer:

Step by step
Remember, a reference angle is a positive acute angle that represents an angle θ of any measurement.
a)
, then its reference angle is 
b)
is in the second cuadrant, then its reference angle is 
c)
, then it is in the first cuadrant and the reference angle is
.
d)
and it is in the third cuadrant, then its reference angle is 