Question

The table shows some values of a function of the form y = ax2 + bx + c.



The value of c, the constant of the function, i

Answer 1

c is the y‑intercept — the value of y when x = 0. (From y = ax^2 + bx + c, substitute x = 0 to get y = c.)

So if the table lists an entry for x = 0, c is that y‑value. If x = 0 isn't in the table, pick any three (x,y) points and solve the system
y1 = a x1^2 + b x1 + c
y2 = a x2^2 + b x2 + c
y3 = a x3^2 + b x3 + c
for a, b, c (or use finite differences: constant second difference = 2a, then find b and c).