If the line with the equation y = 3x + 2 contains the point (r,s), then this equivalent to s = 3r + 2. If we ca prove that, then we're home free.
1. this equation equals 0 only if one or both of the two paranteses are equal to 0. So we get:
If 3r + 2 - s = 0, which is equivalent to s = 3r + 2, then indeed the poin is on the said line.
But this could not be the case. If 4r + 9 - s = 0 but 3r + 2 - s does not equal 0, then the point is noton the line. So 1 is not sufficient.
2. using the same line of thought as before, 2 is insufficient as well.
But if we take the two equations togethere, then it is clear that only if 3r + 2 - s = 0 do they both equal 0, because if we were to consider 4r + 9 - s = 4r - 6 -s = 0, then we get that 9 = -6, which is obviously false. So answer would be C.