A pier forms an 87degrees angle with a straight shore. At a distance of 107 feet from the pier, the line of sight to the tip forms a 39degrees angle. Find the length of the pier to the nearest tenth of a foot.

For the function, f(x) = -5x 2, find f(-4).

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.

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?