I need to find the vertex and the x-intercepts
-b/2a is the formulas to find the vertex of a quadratic equation. You may always switch all of the signs of every term in an equation an so we can rewrite your function as 3x^2-7x-12. -b/2a will give us the x coordinate of the vertex. In this case -b is +7 and 2a is 2(3). Therefore 7/6 is the coordinate for the x value of the Vertex.
Upon plugging in 7/6, we get: 3(7/6)^2-7(7/6)-12=3(49/36)-49/6-12=16.083333333...