Question 128350
Let "x" ft be the width of the rectangle


So lenght will be "3 + x"  ft 


Given area = 40 ft^2



We know that the area of the rectangle is given by lenght times breadth 



40 = x * (x + 3)



40 = x^2 + 3x 



==> x^2 + 3x - 40 = 0 


==> by the method of factoring we find



==> x^2 + 8x - 5x - 40 =  0



==> x(x + 8) - 5(x + 8) = 0


==> x = 5 Or x = -8 


We dont consider the negative values of x.


Therfore x = 5 ft will be the width


and x + 3 = 5 + 3 = 8ft will be the lenght of the rectangle



thus the solution