How do you find the radius of a circle knowing the circumference

Write a polynomial function f of least degree that has rational coefficients, a leading coefficient of 1, and the given zeros. 3, 4+2i, 1+(sqrt)7 the answer is supposed to be: f(x)=x(^5)-13x(^4)+60x(^3)-82x(^2)- 144x+360 what am i doing wrong?

Bernice paid $162 in interest on a loan of $1800 borrowed at 6%. how long did it take her to pay the loan off?

The price of a visit to the dentist is calculated according to the formula 50+100n50+100n where nn is the number of cavities the dentist finds. on your last visit to the dentist, 22 cavities were found. what was the cost of your visit?