This might help explain how to do a very similar problem.... http://www.mathopenref.com/constbisectline.html
Its a binomial. There are two terms
Simple way to see it is to multiply the value opposite of the axis you're flipping it over by -1. For example the point (-5,7) would become (5,7) when reflected over the y-axis, because the point is moving from the left to the right. This means the triangle would be (1,3) (5,3) and (5,7) when reflected over the y-axis. For reflection over the x-axis it would be (-1,-3) (-5,-3) and (-5,-7) because each point is moving down.
3/9 reduces to 1/3 (divide both parts by the GCF 3)
Then use long division to divide 1/3
See attached of what I mean
Which is why
The '3's in 0.333 will go on forever
ANSWER
EXPLANATION
The given function is
This function is defined for values where the denominator is not equal to zero.
The domain is
Or