Find the equation of this line. y=mx+c. image attached!

Can someone answer this question? : )

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.

How can (square root of 25) ^2 be rewritten?