Math help. ASAP! 10 points!

I need help with the last question on my math! please help!

Part 1: Decide whether you would use the graphing, substitution, or elimination method to solve the following system of equations. Explain, in complete sentences, why you chose that method.
Part 2: Solve the following system of equations and show all of your work.

4x + 3y = -1
3x + y = 3

I am not asking for the awnser just an explantation on how to do this.Step by step. Please

Part 1: Substitution, because you have a single "y" in your equation so you can just move the 3x over

so
4x + 3y = -1
y = 3 - 3x

--> then you replace the "y" on your first equation for (3 - 3x) so it would be:
4x + 3 ( 3 - 3x) = -1
4x + 9 - 9x = -1
9 - 5x = -1
-5x = -10
x = 2

----> substitute the "x" on either equation (out of the two originals)

3(2) + y = 3
6 + y = 3
y = -3

Multiply the second equation by 3:

4x + 3y = -1
9x + 3y = 9

Now subtract the second equation from the first equation:

4x - 9x +3y - 3y = -1 - 9

Combine like variables

-5x = -10

divide each side by -5

x = 2

using the x, solve for y using either the first or second equation

4*(2) + 3y = -1

8 + 3y = -1

3y = -1 - 8

3y = -9

y = -3

so x = 2, y = -3