Question 599299
A = LW


104 = (W+5)W


104 = W(W+5)


W^2 + 5W - 104 = 0


Now use the quadratic formula to solve


W = (-b+-sqrt(b^2-4ac))/(2a)


W = (-(5)+-sqrt((5)^2-4(1)(-104)))/(2(1))


W = (-5+-sqrt(25-(-416)))/(2)


W = (-5+-sqrt(441))/2


W = (-5+sqrt(441))/2 or W = (-5-sqrt(441))/2


W = (-5+21)/2 or W = (-5-21)/2


W = 16/2 or W = -26/2


W = 8 or W = -13


Throw out the negative solution to be left with the only solution of W = 8


So the width is 8 m and length is 13 m (since  L = W+5 = 8+5 = 13)