Write the inequality in slope-intercept form 9x+3y> _-12
write the inequality in slope-intercept form 9x-3y< _-12

Treat the inequality sign as an equal sign (=) and move the x (along with its coefficient and sign) to the other side of the equation:
3y>12-9x
3y>3(4-3x)
then divide by 3:
y>4-3x
or
y>-3x+4

Slope intercept form is y = mx + b. M is the slope and B is the y-intercept. 
The first step would be to subtract 9x from both sides. This leaves you with -3y ≥ -9x + 12. 
Next, you would divide both sides by -3. This gives you y ≤ 3x - 4. Make sure you flip your sign from ≥ to ≤ because you divided by a negative number. 
Your inequality in slope intercept form is y ≤ 3x - 4