Don’t understand how to do it help plz

What are the possible rational zeros of [tex]f(x) = x^4+2x^3-3x^2-4x+18[/tex]

Create and solve a linear equation that represents the model, where squares and triangles are shown evenly balanced on a balance beam. assume the weight of a square is 1 unit and the weight of a triangle is unknown.

9/10 divide by -3/15 as a mixed number