
Please consult the "Calculations" section of this ans .

The information we're given is below :
- slope : -1/3
- Point crossed by the line : (3, 6)
As per given information , we can do the following :
- Write the line's equation in point slope form
Point - slope form looks like so :
y-y₁=m(x-x₁)
y-6=-1/3(x-3)
y-6=-1/3x+1
y=-1/3x+1+7
y=-1/3x+6
↑ 

i can help, but you need to write the whole question..
Answer:
The value of x = -1 makes the denominator of the function equal to zero. That is why this value is not included in the domain of f(x)
Step-by-step explanation:
We have the following expression

Since the division between zero is not defined then the function f(x) can not include the values of x that make the denominator of the function zero.
Now we search that values of x make 0 the denominator factoring the polynomial 
We need two numbers that when adding them get as a result -1 and when multiplying those numbers, obtain -2 as a result.
These numbers are -2 and 1
Then the factors are:

We do the same with the numerator

We need two numbers that when adding them get as a result 4 and when multiplying those numbers, obtain 3 as a result.
These numbers are 3 and 1
Then the factors are:

Therefore

Note that
only if 
So since
is not included in the domain the function has a discontinuity in 
20° is the answer if you look on the other side