Find the value of "c" that makes x^2+ 12+ c

Can you me find the missing length. i attached an image.

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.

Devonte is balancing his checking account. his account statement does not include a deposit of $107.00 that he made on november 1st. what is devonte’s actual account balance?