Answer:
You add up all the sides of the shape
Mason needs 9 more seed packets to have a total of 20 plants in his yard.
Simplified:
20-11=9
Answer: The answer is A and D
The answer is no solution
Step-by-step explanation:
The equation is
and 
Subtracting these two equations, we get,

Thus,
is not possible.
Hence, the system of equations have no solutions.