You can substitute any positive odd number for 15. For example: SQRT (X+7) + SQRT (X) = 7 gives X = 9. It works because the difference of any two consecutive squares is always the sum of their square roots.
You can substitute any positive odd number for 15. For example: SQRT (X+7) + SQRT (X) = 7 gives X = 9. It works because the difference of any two consecutive squares is always the sum of their square roots.