Answer:
7) graphing, because they are in the y=mx+b format.
8) substitution, because it tells you what y equals.
9) substitution, because it tells you what y equals.
10) elimination, because you can subtract the x's to equal 0.
11) graphing, because they are in the y=mx+b format.
12) substitution, because it tells you what y equals.
Explanation: