I would only use substitution if I can isolate one of the variables without having to go into fractions.
In this case I would use elimination.
multiply the first by 5 and the second by 2, then add them :
15x - 10y = 40
4x + 10y = -2
19x = 38
x = 2
now sub that back into one of the originals. Take it from here.
Solve the system of equations by Elimination OR Substitution. Explain why you chose one method over the other.
3x – 2y = 8
2x + 5y = -1
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