Question

How many solutions does the system formed by x - y = 2 and ay - ax + 2a = 0 have for a nonzero

number a? Give your answer and complete the explanation.
The system has (select)
solution(s). Rearranging the left side of the 2nd equation and
subtracting 2a from both sides gives-ax + ay =
a. Dividing both sides by-a gives
x-y=
So, the equations describe the same line.

Answer 1

1

y = 0

x = 2

Explanation:

The first thing we want to do to solve a system of equations is to solve one of them in terms of a single variable.

Lets start with x - y = 2

If we add y to both sides we get: x = 2 + y

Now to solve the system of equations we can substitute that value for x into the other equation. In any system of equations a solution for one must be a solution for the other as well.

ay - ax + 2a = 0

When we substitute our value of x into this equation and get the folowing:

ay - a(2 + y) +2a = 0

ay -2a - ay + 2a = 0

All of the terms cancel out on the left side leaving us with:

0 = 0

This means that the only way this system can be solved is if y is equal to 0.

Going back to the first equation x - y = 2

x - 0 = 2 so x = 2

This is the only solution to that system of equations, which means it forms a point instead of a line.