F (x) = x — 1 — 3, and

I do not see any question content, Try re-wording your problem and re-post your question. Once that is done I would love to help.

38+105= 143, 39+104=143, and you will find then adding the numbers on opposite sides, moving inwards yields the answer 138 every time. because of this, you’re going to multiply 138 times the number of pairs, which is 34. therefore, 34*138= 4692(i’m sorry if it’s the wrong numbers, but it’s the right concept)