Question

can someone show me the steps on how to solve to find the zeros of x4-15x2-16, or x3+4x2-3x-12, or x4+2x3+2x2+2x+1

Answer 1

factor as
\[(x^2-16)(x^2+1)=0\]

Answer 2

Finding zeroes just means finding the roots of this quadratic equation

Answer 3

or another way of saying the same thing is where the graph touches the x-axis