Which of the following is not a prime number?

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

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?

If abcde is reflected over the x-axis and then translated 3 units left, what are the new coordinates d?