The discriminant is positive since there are two solutions of f (x) = 0
Which can be seen in the graph as it has two intersections with the x-axis.
f(x)=0 when x=-4 or x=2, because the points (-4,0) and (2,0) belong to the function.
Then:
a) The discriminant is positive.
b) There are 2 real solutions to f(x)=0
c)The coordinate of a point belonging to the f(x) function is (x, f (x)), and that second part of the point is what we need to be 0, in other words we must find the intersections of the graph with y = 0, the x-axis.
The points (-4,0) and (2,0) belong to the given function and intercept the x-axis, then
x= - 4 and x = 2 are the solutions for f(x)=0