Pls Help!

Let  r and s be the roots of $3x^2+4x-12=0$ . Find $r^2+s^2$ . 

 

Notice: This problem is similar to a previously asked question (https://web2.0calc.com/questions/help-help-asap-please) but the equations are slightly different. I have already checked so no need to get on my case about it.