First, multiply each side of the equation by color(red)(12) to put the equation in Standard Form for a linear equation. The standard form of a linear equation is: color(red)(A)x + color(blue)(B)y = color(green)(C)
Where, if at all possible, color(red)(A), color(blue)(B), and color(green)(C)are integers, and A is non-negative, and, A, B, and C have no common factors other than 1
color(red)(12)(x/3 + y/4) = color(red)(12) * 1
(color(red)(12) * x/3) + (color(red)(12) * y/4) = 12
color(red)(4)x + color(blue)(3)y = color(green)(12)
The slope of an equation in standard form is: m = -color(red)(A)/color(blue)(B)
Substituting for color(red)(A) and color(blue)(B) gives:
m = -color(red)(4)/color(blue)(3)