Question 959491
The parabola has the points  (-2,0) and (0,-10) along with (4,18).  Specific equations can be made for each of them.


{{{system(2(-2)^2+b*(-2)+c=0,0+0+c=-10,a*4^2+b*4+c=18)}}}


{{{system(4a-2b+c=0,c=-10,16a+4b+c=18)}}}
Eliminate c through substitution,


{{{system(4a-2b-10=0,16a+4b-10=18)}}}
...and you can finish finding a and b.


Once a and b (and already found c), solved, you can formulate the equation in general form.