What is 4/5 and 9/10 as a fraction in simplest form

I'm terrible at math any here is appreciated.

Click on the graphic until you find the right quotient. (36xa - 30xb) ÷ (-6x2)

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?