Are the 63x and the y being added or multiplied?
You can divide the whole expression by -3:

Recalling that

Let's compare the middle term:

So, we want to complete

Which differs from
by 16. So, if we add 16 to both sides, we have

Answer:
Domain: {0, 1, 2, 3, 4, 5, 6}
Range: {4, 4.5, 5, 5.5, 6, 6.5, 7}
Answer:
Since there are six possible outcomes, the probability is 1/6.