Can someone help me with this please!

At school there are 526 students and 263 are girls about how likely is it that a randomly chosen student will be a boy

What is the length of the segment joining the points at (4,5) and (6,-2) round to the nearest tenth if necessary

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?