Question

Liam owns some rectangular plots of land. All of the plots are the same length, x, and the width of each plot is 5 yards less than the length. The total number of plots Liam owns is 20 more than the length of a plot. If the total area of all the plots Liam owns is 2,688 square yards, which statements about the length of each plot are true?

*The equation x3 − 15x2 − 100x − 2,688 = 0 can be used to find the length of each plot.
**The equation x3 + 25x2 + 100x − 2,688 = 0 can be used to find the length of each plot.
***The equation x3 + 15x2 − 100x – 2,688 = 0 can be used to find the length of each plot.
****The length of each plot is 12 yards.
*****The length of each plot is 8 yards.

Answer 1

We have to:
"All of the plots are the same length, x"
L = x
"and the width of each plot is 5 yards less than the length"
W = x-5
"The total number of plots Liam owns is 20 more than the length of a plot"
20 + x
"the total area of all the plots Liam owns is 2,688 square yards"
A = (20 + x) * (x) * (x-5)
A = (20x - 100 + x ^ 2 -5x) * (x)
A = (x ^ 2 + 15x - 100) * (x)
2688 = (x ^ 3 + 15x ^ 2 - 100x)
x ^ 3 + 15x ^ 2 - 100x = 2688
x ^ 3 + 15x ^ 2 - 100x - 2688 = 0
Answer:
*** The equation x3 + 15x2 - 100x - 2.688 = 0 can be used to find the length of each plot.