Casey's den is 4 feet longer than it is wide. If the​ den's area is 140 square​ feet, what are the dimensions of the​ room?

Answer 1

L=4+W

LW = 140

(4+W)(W) = 140

W^2 + 4W = 140

W^2 + 4W -140 = 0

factor

(W+14)(W-10) = 0

set each factor = 0 and solve for W

W=-14 and W=10, ignore the negative dimension

W = 10 feet in width

L=4+10 = 14 feet in length

14 x 10 feet = 140 square feet