Write the quadratic function for the parabola having vertex(4,2) and passing through the point (1,11)

So the function we are looking for should look like f(x)=a(x-1)2-2, and since the parabola passes through (4,5), we have 5=a(4-1)2-2, which means 5=9a-2, so a = (7/9) and f(x) = (7/9)(x-1)2-2.