Answer:
The required equation is: 
Step-by-step explanation:
We need to find equation from the table given
x f(x)
3 -5
7 -2
11 1
15 4
We can write equation in the form of 
where m is slope and b is y-intercept.
Finding Slope
We can used the slope formula to find slope: 
From the table we have: 
Putting values and finding slope

So, we get slope 
Now, finding y-intercept
Using the slope
and point (3,-5) we can find y-intercept

The y-intercept is 
So, the equation having slope
and y-intercept
will be:

The required equation is: 
All you need to do here is know where and how to plug in the numbers. In each equation, you'll have an initial fee, and an hourly fee, so your equation will be
y = i + hx, where i = the initial fee, and h = the hourly fee
So, after plugging them in, here's what you get:
Doors Galore: y = 40 + 50x
G&H: y = 60 + 40x
58 plus tip of .20
so
58 times 0.2 = 11.6 is the tip
now we add tax (Presuming we son't tax the tip)
58 times 0.07 = 4.06 the tax
so its
58 + 11.6 + 4.06 = $73.66 total cost
Answer:
8 ft², 21.8ft², and 11.2ft²
Step-by-step explanation: