Area = Length x width.
30 = w x 3w +1
Simplify:
3w^2 + w = 30
Subtract 30 from both sides:
3w^2 + w -30 =0
Factor
(w-3)(3w+10) = 0
Solve for the w's:
w = 3 and x = -3 1/3
Since the number cant be negative w = 3
The width = 3 cm.
