I misread the initial problem. Thank Michael for noticing.
Below is the corrected version.
We have the length is 1 ft less than 4 times the width so
L = 4W-1
Area = L(W) = 60 ft2
(4W-1)(W) = 60
4W2-W = 60
We can factor this by grouping
Multiply the coefficient of the squared term, 4, by
the constant, -60 giving -240.
Look for factors of -240 that add to the coefficient
of the x term, -1.., (-16)(15) = -240, -16+15=-1
Replace the -W with -16W + 15W fiving
4W(W-4) + 15(W-4) =0
(4W+15)(W-4) = 0
4W+15=0 or W-4=0
W=-15/4 or W=4
Disregard the negative answer so W = 4
L = 4W-1=4(4)-1=15
Our dimensions are 15 ft by 4 ft