URGENT MATH please
posted by 11th grade .
Chris cuts half a rectangular lawn, 40m by 30m, by mowing strips of equal width around the perimeter. Jerri cuts the small rectangle in the middle that's left. How wide a strip does Chris cut so that they share the work equally?
Solve by using quadratic formula.

Did you make a sketch ?
Let the width of the cut done by Chris be x m
That leaves a rectangle of 402x by 302x to be cut by Jerri.
(402x)(302x) = (1/2)(40)(30)
4x^2  140x + 1200 = 600
x^2  35x + 150 = 0
(x5)(x30) = 0
x = 5 or x = 30 , but x = 30 makes no sense
x = 5
The strip should be 5 m wide.