Hi, I have a question regarding the above solution. While I understand the solution in the video, I wanted to know why Greg did not test for extraneous roots by plugging in the values of x to see which ones work.
In the solution, Greg rewrites the equations as x^2 +3x +2 =0 and x^2 +3x -2 =0. He then goes on to find the discriminant of the two equations and proves that since both equations have a positive discriminant there must be four solutions.
However, don’t we have to plug back all the potential values of x and check if the absolute value holds true to conclude that all 4 roots work?