Hello, im doing this math homework in quadratics and i cant figure out this one

Determine the equation (in standard form) of the parabola that has a y-intercept of 3, and that passes through the points (1,9) and (-2,15)

this is supposed to be an inquiry question, i guess its relatevely easy but i dont know which one is the vertex and how do i use the y-intercept to help me solve it?