Alice backyard has 6.25 by 6.25 m patio she would like to build a 1.5 m wide extension around three sides of the patio as a figure shows she will by 0.25 by 0.25 m tiles that comes to 25 to a package

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?