To find the area you need to multiply.
Use dimensional analysis:

Since we multiplied a numerator and a denominator by centimeters, we are only left with meters.
This answer is already is three significant figures by default.
The equation of the line is
y = 5x-11
You can solve this by dividing the baches into the total amount of donuts.
147/7=21
Each batch has 21 donuts.