I assume you mean "if you have " so the x-intercepts are where y= 0: . Of course, you find them by solving that equation. I recommend crossing your fingers and hoping that there is at least one rational root. The rational root theorem tells us that if there is a rational root, it must be an integer that evenly divides the constant term, 30. The only possible rational roots are , , , , , , , . Try those and see if one or more satisfy the equation. If one does, you can divide by the corresponding factor to reduce to a quadratic equation.