Problem: Use addition or Substitution to find the value of x for this set of equations
12x-5y=30
y=2x-6
1) 12x - 5y = 30
2) y = 2x - 6
Might as well use substitution.
12x - 5y = 30
12x - 5(2x - 6) = 30
12x - 10x + 30 = 30
2x + 30 = 30
2x + 30 - 30 = 30 - 30
2x = 0
x = 0