Plz plz i need help i dont know

Simplify 15(x - 4)(x -1)-3(x + 4)(x - 1) with steps

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?

Which of the following is the explicit rule for a geometric sequence defined a recursive formula of a -5a for which the first term is 23?