When solving for this problem, replace x with the first coordinate and solve. if the answer is what you have for the second, it is correct. The first number in an ordered pair is your x and the second is your y. So I would rewrite the equation like this and solve.
y=7x-19 y=7x+21
2=7(3)-19 9=7(4)-19 2=7(3)+21 9=7(4)+21
2=21-19 9=28-19 2=21+21 9=28+21
2=2 9=9 2=42 9=49
as you can see it is the first equation.
