Question

What’s the standard form of the quadratic equation

Answer 1

 y = ax^2 + bx + 7    because when  x = 0 y = 7

when x = -1 y = 14 so we have
14 = a - b + 7
so a - b = 7...............(1)
when x =  1 y = 4
so 4 = a + b + 7
a + b = -3.................(2)
Adding equations (1) and (2) we eliminate b so:-
2a = 4
a = 2
Substitute  a = 2 in equation (1)
2 - b = 7
b = -5 

so our equation is y = 2x^2 - 5x + 7