Question 975090
y = a(x-h)2+k
y= a(x-5)^2 +12

Find a by using the point

15=a(7-5)^2 +12

15=4a+12
a=(3/4)

y=(3/4)(x-5)^2 +12

y=(3/4)x^2-7.5x+30.75

{{{graph(300,300,-10,10,-10,30,(3/4)x^2-7.5x+30.75)}}}