answer: all of the odd numbers were opened
the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.
i think something is missing in your question because y-1=(x-12) would not pass through the point (-4,-3). because if you replace x by -4 your are supposed to find y=-3 which is not the case her. if you replace x by -4 you find =-15.
i assume the right equation is y-1=1/4*(x-12) because this one is passing through both your points (if you are interested to know how i found that out i can tell you).
in this equation if i replace x by -4 i find y=-3 and if i replace x by 12, i find y=1 so the line representing this equation is passing through those 2 points.
then the standard form of the equation is finding an expression of y in function of x
hope that .
do you confirm there was a mistake in the question?