Choice B is the correct answer. You can do this yourself by graphing on Desmos.
Answer: after adding them -7r^2+12r-8
Step-by-step explanation: add them
The length would be 90 cm. For every 1 cm of actual size it will be increased by 9. So.....10 x 9 = 90 cm.
I believe the slope is 0 because it they are both horizontal lines? I may be wrong though.