
William W. answered 10/27/19
Math and science made easy - learn from a retired engineer
Let "x" be the width of the walkway. The total length is then 15 + x + x or 15 + 2x. And the total width is 12 + x + x or 12 + 2x. Since (for the total shape) Area = LTotal * WTotal and the Area is 754, then we can say:
LTotal * WTotal = 754 or
(15 + 2x)(12 + 2x) = 754
Multiplying this out gives us:
180 + 54x + 4x2 = 754 or
4x2 + 54x - 574 = 0 or (dividing by 2): 2x2 + 27x - 287 = 0
Factoring, we get (x - 7)(2x + 41) = 0 and then (setting each piece equal to zero), x = 7 and x = -41/2
Since the walkway can't be a negative dimension, we can say the walkway is 7 feet wide.
Jose C.
Thanks10/27/19