Respuesta :

Area of a rectangle=lenght x width.
width=x
length=x+3
we can suggest this equation:
x(x+3)=40
x²+3x=40
x²+3x-40=0
we solve this square equation:
x=[-3⁺₋√(9+160)] / 2
x=(-3⁺₋13)/2
we have two solutions:
x₁=(-3-13)/2=-8  this solution isn´t valid.
x₂=(-3+13)/2=5

lenght=x+3=5+3=8

Answer: the lenght, in inches, of the rectangle  is 8 .
(2) 8
  Let's say W=the width of the rectangle 

if width times length equals the area, then... 

W x (3+W)=40 
  Length = 8 
Width = 5 
I started by factorising 40: 
2, 2, 2, 5. 
Then you just find a way to arrange those numbers that works