Answer:
The correct option is option B. It has one solution, and it's x=-3
Step-by-step explanation:
We have the following system of equations:
5x+7 = 2y (1)
y-9x=23 (2)
Step 1: Solve for 'y' in equation (2):
y-9x = 23
y = 9x + 23
Step 2: Substitute in equation (1):
5x + 7 = 2y
5x + 7 = 2(9x + 23)
5x + 7 = 18x + 46
Step 3: Solve for x:
7 - 46 = 18x - 5x
-39 = 13x
x= -3
So the correct option is option B. It has one solution, and it's x=-3
215 is the answer because 78-35 =43 43×5=215
The speed is the ratio between the distance and the time:

Data:
d=6343miles
t=9h

Then, the plane traveled at a speed of 704.77 miles per hour.
This depends on a lot of factors. A persons weight, height, etc. It also depends on how many calories they want to burn or if they are just looking to run for fun. A lot of different factors play into a persons time to jog.
The difference between the coat cost for Delaware vs Fairfield is $0.60
Explanation:
For Delaware: 80 × .0725 = $5.80
80+5.80= $85.80
For Fairfield: 80 × .065 = $5.20
80+5.20=$85.20
85.80-85.20=0.60