Answer:

Step-by-step explanation:
Given
The attached triangle
Required
Find y
The attached triangle is isosceles; so:

Also, we have:
--- angles in a triangle
Substitute: 

Collect like terms


To start break even they need to sell 100 but if they want to make profit they need to sell 101 because you can use the equation y = .75x - 55
Answer
Elena must have substracted 1/2x from both sides of the equation.
Lin must have multiplied both sides of the equation by 2
Explanation
The equation given is

For Elena to have arrived at

Then Elena must have substracted 1/2x from both sides of the equation.
That is;

For Lin to have arrived at

It shows Lin must have multiplied both sides of the equation by 2
That is;
Answer: Lcm=60
Step-by-step explanation: but if you want lcf its always 1