Let's find the equation of the line with slope 1/4 that passes thru (3,-6):
y+6 = (1/4)(x-3). Mult both sides by 4 to elim. the fraction (1/4):
4y + 24 = x - 3. Now let y = 9 and solve for x:
36 + 24 = x - 3 => 63 = x (answer)
You should check this. Subst. x = 63 into y+6 = (1/4)(x-3). Do you get y = 9?