Please help me answer both these questions... :)

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?

You are at a restaurant and owe $56.20 for your meal. you want to leave an 18% tip. approximately how much is your tip?

The ph level of a blueberry is 3.1 what is the hydrogen-ion concentration [h+] for the blueberry