Marta walked at 3.1 miles per hour for 0.91 hours. How far did she walk?

2.808 miles. 

Step-by-step explanation:

Marta walked in 1 hour = 3.9 miles (rate of walking per hour).

what i would say the best answer is a. 40.5

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.