How do I find all the rational zeros of function?

1 Answer

To find the zeroes of a function, f(x)f(x), set f(x)f(x) to zero and solve.
For polynomials, you will have to factor.

For example: Find the zeroes of the function f(x) = x^2+12x+32f(x)=x2+12x+32

First, because it's a polynomial, factor it
f(x) = (x+8)(x+4)f(x)=(x+8)(x+4)

Then, set it equal to zero
0 = (x+8)(x+4)0=(x+8)(x+4)

Set each factor equal to zero and the answer is x=-8x=8 and x=-4x=4.

*Note that if the quadratic cannot be factored using the two numbers that add to this and multiple to be this method, then use the quadratic formula (-b +- sqrt(b^2-4ac))/(2a)b±b24ac2a

to factor an equation in the form of ax^2+bx+cax2+bx+c.