Answer:
y=-6
Step-by-step explanation:
The y value isn't changing when the x value does. This means there is no rate of change or gradient. So in y=mx+c m=0 so we get y=c, c is always -6.
Answer:

Step-by-step explanation:
We can rewrite the equation as

Notice that we have
in both the numerator and the denominator, so it looks like we can divide it out. However, what if
is
? Then we would have
, which is undefined. So although it looks like the numerator and denominator can be simplified, the resulting function we would get from simplification would not have the same behavior as this one (since such a function would be defined for
, but this one is not).
A point of discontinuity refers to a particular point which is included in the simplified function, but which is not included in the original one. In this case, the point which is not included in the unsimplified function is at
. In the simplified version of the function, if we plug in
, we get

So the point
is our only point of discontinuity.
It's also important to distinguish between specific points of discontinuity and vertical asymptotes. This function also has a vertical asymptote at
(since it causes the denominator to be 0), but the difference in behavior is that in the case of the asymptote, only the denominator becomes 0 for a specific value of 
The way that I memorised how to do sin, cos, and tan is by the following: SOH, CAH, TOA
SOH = Sin is OPPOSITE / HYPOTENUSE
CAH = Cos is ADJACENT / HYPOTENUSE
TOA = Tan is OPPOSITE / ADJACENT
For example if we were to solve question 5
Sin T = 6 root 2 / 19
Cos T = 17 / 19
Tan T = 6 root 2 / 17
Repeat the steps for question 6
For the rest of the questions (7,8,9) you have to take the information given and figure out if you should us Sin, cos, or Tan. then plug the numbers in the calculator and while doing sin ^ -1, cos ^ -1, tan ^ -1
for example on question 7, to find the angle x they have given you the hypotenuse and the adjacent side so
cos x = 9 / 18
to find x plug: cos^-1 (9/18) in the calculator
On a phone here and no access to paper but you must first find the midpoint of AC which is the average of the coordinates. The perpendicular bisector will have a gradient that multiplies by AC's gradient to make -1. This will obviously pass through its mid point so as long as you know how to use y=mx+c you should be good.