Question

1. When solving systems of equations, how do you determine what method to use?
2. solve the system and show your steps
2y = x + 1
–2x – y = 7

Answer 1

You can use elimination or substitution.

Answer 2

For substitution, you can divide the first equation by 2 get your Y and substitute it.

Answer 3

\[y = \frac{ x }{ 2 } + \frac{ 1 }{ 2 }\]
now you have a y, that you can use to plug in for y for the 2nd equation.

Answer 4

For elimination, you do the same method, except you are elimiating ONE variable to get just ONE, like for instance, eliminate y and get only x's.
but you must have it in the form:

1. (x) + (y) = number
2. (x) - (y) = number
notice how you can eliminate Y if you add both together to get:

2x = number
then divide by 2 to get x. Then plug it back in and solve for Y! :)

Answer 5

You can also use gauss elimination and put it into a matrix