Answer:
Choice 4 (s - 3 = 12)
Step-by-step explanation:
I think you made a reading error on this question, as it said "for which equation is s = 9 not the solution?" No need to fret though, this can easily be solved by substituting 9 into the variable s of each equation.
1. We know it's not choice 1 (s + 6 = 15), because doing 9 + 6 does equal 15.
2. We know it's not choice 2 (7 + s = 19), because doing 7 + 9 does equal 16.
3. We know it's not choice 3 (13 - s = 4), because doing 13 - 9 does equal 4.
4. Choice 4 (s - 3 = 12) is the correct answer because doing 9 - 3 equals 6, not 12. Thus this equation is incorrect, meaning this is the correct choice.
Choice 4/D is the correct choice.
