Answer:
![y=4x+3](https://img.qammunity.org/2021/formulas/mathematics/middle-school/xkmc5v858vxmae2h1yfsggkmf4rus13wuy.png)
Explanation:
By definition the Slope-Intercept form of an equation of a line is:
![y=mx+b](https://img.qammunity.org/2021/formulas/mathematics/middle-school/yj5waqmoy4i54laybzhhshd88hyo5w5rj5.png)
Where "m" is the slope of the lines and "b" is the y-intercept.
You have the following equation of the line given in the exercise:
![3y-12x = 9](https://img.qammunity.org/2021/formulas/mathematics/middle-school/fao1j63z9m7cy8kedyafk5u1b058b5ygqe.png)
Then, in order to write it in Slope-Intercept form, you need to solve for the variable "y".
The steps are shown below:
1. You must apply the Addition property of Equality adding
to both sides of the equation:
![3y-12x+12x = 12x+9\\\\3y=12x+9](https://img.qammunity.org/2021/formulas/mathematics/middle-school/17ybfmb8zqi20k988hc0hq686lwpo3q5kx.png)
2. Finally, you must apply the Division property of Equality dividing both sides of the equation by 3. Then, you get:
![(3y)/(3)=(12x+9)/(3)\\\\y=4x+3](https://img.qammunity.org/2021/formulas/mathematics/middle-school/5jmusdqpkrv10elpg75fnu1mzhtvxo9ros.png)