Micah was asked to add the following expressions:

First, he combined like terms in the numerator and kept the common denominator
First step is correct. He added the like terms in the numerator, because the denominators are same.

So he got , 
In the next step, he cannot cancel out x^2 from the top and bottom . Because x-4 and 3x+2 are added with x^2
If we have x^2 is multiplied with other terms at the top and bottom , then we can cancel out x^2.
So Micah added the expression incorrectly. Final answer is not correct.
Answer:
Step-by-step explanation:
x²+y² = 5²
3²+y² = 25
y² = 16
y = ±√16 = ±4
Since the terminal side is in quadrant IV, y = -4
sinθ = -4/5
A dilation is a transformation, with center O and a scale factor of k
that is not zero, that maps O to itself and any other point P to P'.
The center O is a fixed point, P' is the image of P, points O, P and P'
are on the same line.
Thus, a dilation with centre O and a scale factor of k maps the original figure to the image in such a way that the<span>
distances from O to the vertices of the image are k times the distances
from O to the original figure. Also the size of the image are k times the
size of the original figure.
In the dilation of triangle TUV</span>, It is obvious that the image <span>T'U'V' is smaller than the original triangle TUV and hence the scale factor is less than 1.
</span>The ratio of the
distances from A to the vertices of the image T'U'V' to the distances
from A to the original triangle TUV is the scale factor.
The scale factor = 3.2 / 4.8 = 2/3