Part 1 (3 points) : When solving systems of equations, how do you determine what method to use?

Part 2 (10 points) : Choose 1 system of equations from the choices below. Then, solve the system and post your solution, showing your steps so that other students can see which method you chose.

–y + 3x = 6
y = –6x + 12

6x – 4y = 54
–9x + 2y = –69

2y = x + 1
–2x – y = 7

Question

Part 1 (3 points) : When solving systems of equations, how do you determine what method to use?

Part 2 (10 points) : Choose 1 system of equations from the choices below. Then, solve the system and post your solution, showing your steps so that other students can see which method you chose.

–y + 3x = 6
           y = –6x + 12

6x – 4y = 54
           –9x + 2y = –69

2y = x + 1
           –2x – y = 7

farmdawgnation · Answer

chrissyj, do not continue reposting the same question over and over again. Feel free to ask for more attention in chat if you feel you need it! Thanks, and welcome to OpenStudy!

turingtest · Answer

1.
when at least one of the variables has the same coefficients in both equations
or is an simple multiple of the same variable in the other equation, then elimination is a good strategy.

When one of the variables can be easily isolated into a simple expression, then substitution is a good strategy.

turingtest · Answer

I'll give the first steps of the rest:
2. substitution:

 –y + 3x = 6
           y = –6x + 12

substituting the second equation into the first we get

-(-6x+12)+3x=6

which can be solved for x

after finding x you can use the second equation above directly to find y