Part A:
y=mx+b
621=83(7)+b
Part B:
621=83(7)+b
621=581+b
621-581=b
b=40
Insurance cost is 40$
Answer: Store C by far, less money more time.
Step-by-step explanation:

The value of the discriminant is
12.
Since the discriminant is greater than zero, the equation has
two real solutions.
1. $9500 because 10*950=9500
2. $95 because 950/10=95
( can explain further )
Everything you need is in the picture attached.