Question 312635
substitute the two points and you have two equations with two unknowns


7 = a(2-1)^2 + k ___ 7 = a + k


16 = a(-1 -1)^2 + k ___ 16 = 4a + k


subtracting equations ___  9 = 3a  ___  3 = a


substituting  ___  7 = (3) + k  ___  4 = k