How do you get the zeros x3 4x2 9x plus 36?

Answer 1

Just like there is a formula for solving quadratic equations, there is one for solving cubics, but it is much larger. Cubics three roots (or zeroes, or solutions). The formula is too large to be read comfortably here, so I've included a link to the relevant Wikipedia page where you can see the full formula; check under "related links".

Answer 2

First set the function equal to zero. x^3 - 4*x^2 - 9*x + 36 = 0 Then factorise the left hand side. x^2*(x-4) - 9*(x-4) = 0 (x-4)*(x^2-9) = 0 or (x-4)*(x-3)*(x+3) = 0 For the product [multiple] of these three factors to be zero, one of them must be zero. So, x-4 = 0 or x-3 = 0 or x+3 =o ie x = 4 or x = 3 or x = -3