A laptop computer consumes about 20 watts of electricity per hour when operating. At 10 cents per kilowatt-hour, how much does a laptop cost to operate for 5 hours?

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?