Solve for both X and Y

Taking algebra two apex courses and need with these questions

Jenisey has $24 to spend on seven pencils. after buying them she had $10. how much did each pencil cost.?

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?