Question

The graph of a quadratic function is given. Determine the function's equation.
A. j(x) = -x2 + 1

B. f(x) = -x2 - 2x - 1

C. h(x) = -x2 - 1

D. g(x) = -x2 + 2x + 1

Answer 1

since its a quadratic function the general equation can be given as \[f(x) = a(x-b)^2 + c\]

where c is the maximum(or minimum), b is the point where the max(or min) occurs

Both of those values can be obtained from the graph

Also you can get the sign of the a by looking at whether the graph gives a maximum or a minimum (if its a maximum a <0, minimum a>0)