Question 1058091
One of the points given is a y intercept.  Using it to form an equation will immediately give you the value for c.  With that known, you can cut your system down to two equations in two unknown coefficients.  You know by this time how to solve a "linear" system of two equations in two unknowns.


{{{a*0^2+b*0+c=1}}}
{{{c=1}}}


Continue with the system
{{{system((-3)^2*a+(-3)b=10-1,(2^2)a+2b=15-1)}}}.