An object of height 6 cm is placed at a distance of 20 cm in front of a concave lens of power -8 D. Find the size of the image.

If it is an equal sign, the answer would be 2 and -42 and -4 cut a number line into three section. choose a number in each section to test which one worksa number to the left of -4 (that is, smaller than -4), say -5, plug x=-5 in there to see if the result is > 0.do the same with a number between -4 and 2, and a number larger than 2,you will see that the answer is either x< -4 or x> 2