In a full factorial experiment, there are usually 32 or 2⁵ treatments. This implies that there are usually 2 levels and 5 factors. From the description below, there is a list of the 32 treatments.
-15x-40=15 then add 40 to both sides to get the constants on 1 side and variables on the other -15x=25 now you just divide by -15 x = -1.67 or x = -1/3
