Just help me on 6 and 7 please

Which undefined geometric term is described as a location on a coordinate plane that is designed by an ordered pair (x,y) ?

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?

Write a function for a rotation 90 degrees counter clockwise about the origin, point 0