The equation for Louis's purchase is: 
The equation for Kate's purchase is: 
The equation for Biff's purchase is: 
Step-by-step explanation:
First of all we have to define variables for each item involved in the purchase
Let x represent burger
y represent soda
z be the slice of pizza
Then
"Louis bought a burger and soda for $8"

"Kate purchased a slice of pizza and soda for $9"

"Biff purchased a burger, a slice of pizza and a soda for $13.50"

The equation for Louis's purchase is: 
The equation for Kate's purchase is: 
The equation for Biff's purchase is: 
Keywords: Linear Equations, Variables
Learn more about Linear equations at:
#LearnwithBrainly
Answer:
Its A :))
Step-by-step explanation:
Answer:
45°
Step-by-step explanation:
= 45°
Answer:
A and B
Step-by-step explanation:
Parallel lines are lines which have the same slope. Perpendicular lines have negative reciprocal slopes.
For the options:
A. Both equations have 7/5 as the slope. They are parallel.
B. The slopes are 1 and -1. These are perpendicular.
C. The slopes are 9/2 and are parallel.
D. The slopes are 7/3 and -3/7. They are perpendicular.
The solution is A and B.