Answer:
The answer is 120 feet.
Step-by-step explanation:
The area of the field (A) is:
A = w · l (w - width, l - length)
It is known:
A = 12,000 ft²
l = w - 20
So, let's replace this in the formula for the area of the field:
12,000 = w · (w - 20)
12,000 = w² - 20
⇒ w² - 20w - 12,000 = 0
This is quadratic equation. Based on the quadratic formula:
ax² + bx + c = 0 ⇒
In the equation w² - 20w - 12,000 = 0, a = 1, b = -20, c = -12000
Thus:
So, width w can be either
or
Since, the width cannot be a negative number, the width of the field is 120 feet.
