First set everything to 0.

Giving you A= 1 , B= 1 and C= -5
Then input everything into the quadratic formula and either solve by hand or use a calculator.
Note exact values are found by hand, decimals are found using a calculator.
Answer:
k = 11
Step-by-step explanation:
Given the points are collinear then the slopes between consecutive points are equal.
Using the slope formula
m = 
with (x₁, y₁ ) = (5, 1) and (x₂, y₂ ) = (1, - 1)
m =
=
= 
Repeat with another 2 points and equate to 
with (x₁, y₁ ) = (1, - 1) and (x₂, y₂ ) = (k, 4)
m =
, then
=
( cross- multiply )
k - 1 = 10 ( add 1 to both sides )
k = 11
X + y = 10
x - y = 2
add the equations together
2x = 12
x = 6
6 + y = 10
y = 3
The domain of (f/g)(x) considers the domains of g(x) and f(x) and makes sure that g(x)≠0
because (f/g)(x)=f(x)/g(x)
and division by 0 is not allowed
the domains of f(x) and g(x) are all real numbers
now find what make g(x)=0
0=x-9
9=x
9 is restricted from the domain
domain is all real numbers except 9
so


the domain is all real numbers except for 9