Let's first define the variables:
x = width
300 - 2x = long
The area will be:
A = (x) * (300 - 2x)
A = 300x - 2x²
We look for the maximum area, for this, we derive:
A '= 300 - 4x
We match zero:
0 = 300 - 4x
x = 300/4 = 75
Therefore, the width is:
x = 75 feet
The length is:
300 - 2x = 300 - 2 (75) = 300-150
150 feet
Answer:
Part A:
The maximum area will be:
A = (150) * (75) = 11250 square feet
Part B:
The dimensions are:
Length = 150 feet
width = 75 feet
Area=legnth times width
if legnth=x
and
area=400
400=x times width
wait
SQUARE painting
legnth=width
width=x
400=x times x
400=x^2
sqrt both sides
20=x
answer is 20 in
equation is
400=x times x
So firstly, multiply both sides by t: 
Next, add both sides by v0, and your answer will be: 