Given the quadratic function f (x) = AX2 + BX + C, f (2) = 0, f (- 5) = 0, f (0) = 1, find the quadratic function

Given the quadratic function f (x) = AX2 + BX + C, f (2) = 0, f (- 5) = 0, f (0) = 1, find the quadratic function

If f (x) = AX2 + BX + C is a quadratic function, then a is not equal to 0
So, f (2) = 4A + 2B + C = 0; (1)
f(-5)=25a-5b+c=0; (2)
f(0)=c=1 (3)
(2) (1) 21a-7b = 0, that is, B = 3A
Substituting B = 3A, C = 1 into (1)
The solution is a = - 1 / 10,
Substituting a into b = 3A, B = - 3 / 10
So: F (x) = - 1 / 10x2-3 / 10x + 1
This step is already very detailed