I guess u want to know the quadratic function and its formula is, AX*2 + BX + C. Otherwhise you want to know how to get 0 and get the Xm if you want to know how to solve a quadratic. That formula is, (-B +/- (B*2 - 4AC) ) . 1/2 (where A, B and C are the number at the original function).
Step-by-step explanation: Once you subtract from both sides, in order to solve for y (as the equation needs to be in the slope-intercept form, otherwise known as ), you end up with , which is the right answer. It is the correct answer because the y-intecept shown in the equation matches what is on the graph, in addition to the fact that the slope is just .