

When

, you're left with

When

or

, you're left with

Adding the two equations together gives

, or

. Subtracting them gives

,

.
Now, you have



By just examining the leading and lagging (first and last) terms that would be obtained by expanding the right side, and matching these with the terms on the left side, you would see that

and

. These alone tell you that you must have

and

.
So the partial fraction decomposition is
Part A: This data does represent a function because no value of x is repeated.
Part B: If x = 6 for the relation f(x) = 7x - 15, then f(x) will equal 27. The function f(x) = 7x - 15 will have the greater value
Part C: If f(x) is equal to 6 then x will equal 3
X = (12 +- sqrt (144 -4(7)(3))/14
x = (12 + - sqrt (144 - 84))/14
x = (12 + - sqrt(60))/14
x = (12 + - 2sqrt 15))/14
x = (6 + - sqrt 15) / 7
the upside down T is always perpendicular so the answer is b. :)
53.70 - 9.60 = 44.10. 44.10 / 2 = 22.05. Each friend paid (not including the tip) $22.05.