What is the equivalent expression of 12d4

Find the sum of 4x^{2} -4+6 and -7^{2} +3x+1

Diane owes $387 to her brother. if she debits her bank account $161.25 a month to pay him back, how many months will it take her to pay off the debt?

Ricky takes out a $31,800 student loan to pay his expenses while he is in college. after graduation, he will begin making payments of $190.66 per month for the next 30 years to pay off the loan. how much more will ricky end up paying for the loan than the original value of $31,800? ricky will end up paying $ more than he borrowed to pay off the loan.