If AB is 6 and AC is 4. Look at how BC it longer than AC but shorter than AB. The number in between would be 5 so the answer is 5cm.
If their mean is 5, then the numbers add up to 25.
Here are a few sets that do the job:
1, 2, 3, 4, 15
10, 20, 30, 40, -75
+2, -2, +99, -99, 25
1, 5, 5, 5, 9
Factor out factors that are shared by all terms.
In this case, factor -6x
-6x³ -12x² -18x = -6x(x² + 2x + 3)
-6x(x² + 2x + 3) is your answer
hope this helps