Answer:
width=9 inches
length=12 inches
Step-by-step explanation:
The perimeter of a rectangle can be expressed as;
P=2(L+W)
where;
P=perimeter of the rectangle
L=length of the rectangle
W=width of the rectangle
In our case;
P=42 inches
L=w+3
W=w
replacing;
42=2(w+w+3)
42=2 w+2 w+6
42=4 w+6
4 w=42-6
4 w=36
w=36/4=9
w=9
width=9 inches
length=9+3=12 inches