Respuesta :

3x+4y=12
-3x     =12-3x
4y = -3x +12
4y/4 = -3/4x +3
y = -3/4 +3

3x - 4y=12
-3x        -3x
-4y = -3x +12
-4y/-4 = 3/4 x -3
y = 3/4 -3

If the equation is 3x +4y =12 the slope is -3/4
If the equation is 3x -4y=12 the slope is 3/4