Answer:
8000
Step-by-step explanation:
The number will be ...
(400 m^2)/(500 cm^2) = 0.8 (m/cm)^2 = 0.8 ((100 cm)/(1 cm))^2
= 0.8·100^2 = 8000
Fiona can cut 8000 rectangles from the plastic sheeting she bought.
3b^2 - x = -9b^2
x = 3b^2 +9b^2
x = 12b^2
3b^2 -12b^2 = -9b^2
hope this will help you