Anyone help please I’ll give you points

Which graph corresponds to the function f(x) = x2 + 4x – 1?

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.

Typically a point in a three dimensional cartesian coordinate system is represented by which of the following answers in the picture !