Question 324494
Assuming your chosen field is lawn care, how about this one?
:
Glenn cuts half a rectangular lawn, 40m by 30m, by mowing strips of equal width around the perimeter.
 Brad cuts the small rectangular left.
 How wide a strip does Glenn cut so that they share the work equally?
:
Find the area of the whole lawn: 40 * 30 = 1200 sq/m
then half of lawn: 1200/2 = 60 sq/m
:
Let x = width of the strip mown by Glenn equal half the area
:
Dimension of the remaining rectangle
(40-2x) by (30-2x) 
:
Half the area:
(40-2x)(30-2x) = 600
FOIL
1200 - 80x - 60x + 4x^2 = 600
:
1200 - 140x + 4x^2 - 600 = 0
Arrange as a quadratic equation
4x^2 - 140x + 600 = 0
Simplify, divide by 4
x^2 - 35x + 150 = 0
Factor
(x-5)(x-30) = 0
The reasonable solution is:
x = 5 m is the width of Glenn's strip
:
:
Check solution by finding the area of the remaining rectangle
40-10)*(30-10) = 600
:
:
Note if they insist on the quadratic formula, solve;
{{{x = (-(-35) +- sqrt(-35^2-4*1*150 ))/(2*1) }}}