Answer:
Step-by-step explanation:
by synthetic division
x+8=0
x=-8
-8| 1 -1 -72
| -8 +72
------------------
1 -9 | 0
x-9
width=x-9
or second method
x²-x-72=0
x²-9x+8x-72=0
x(x-9)+8(x-9)=0
(x-9)(x+8)=0
we know area of rectangle=length×width
if length=x+8
then width=x-9
