A positive function means that the slope or rather the gradient of the graph at that point is positive.
The negative gradient always slides from right to left. i.e the intervals for which the function is negative are; between x = -8 and x = -4 and between x = 0 and x = 8.
The function is positive when the slope slides from left to right. From the graph that it is between x = -4 and x = 0.
From the choices the function is positive at, (-2,4)
A square rotated about its center by 360º maps onto itself at 4 different angles of rotation. You can reflect a square onto itself across 4 different lines of reflection.
