The double implication "if and only if" is graphically represented by an arrow pointing in both direction, so the correct writing is

Answer:
The 28% rule states that you should spend 28% or less of your monthly gross income on your mortgage payment (e.g. principal, interest, taxes and insurance). To determine how much you can afford using this rule, multiply your monthly gross income by 28%
Refer the attached figure for the graphic representation of the given quadratic equation.
<u>Step-by-step explanation:</u>
Given expression:

To find:
The graphic representation of the given quadratic function
For solution, plot the graph to the given quadratic equation.
The standard form of the equation is

When comparing with given quadratic equation,
a = 1, b = - 8, c = 24
Axis of symmetry is 
By applying the values, the axis of symmetry of given equation is

The vertex form of quadratic equation is 
Where, (h,k) are the vertex.
Convert the quadratic equation into vertex form.
By completing the square,



On comparison,
(h , k) = (4 , 8)
Now, plot the equation with vertex (4,8) [refer attached figure].
Answer:
457.6
Step-by-step explanation:
if he drove 208 on 5 gallons, 208/5 =41.6 miles per gallon. 41.6*11= 457.6
The answer would be : 5x+1
Just add 2x and 3x