Thread: Find out expression of a cubic function

i have a question i have no idea how to solve.....


Find an expression for a cubic
function f if f(3) = 54 and f(-3) = f(0) = f(4) = 0.

f(x) =_________________________


Does anyone know how to solve this.

Originally Posted by Sneaky

i have a question i have no idea how to solve.....


Find an expression for a cubic
function f if f(3) = 54 and f(-3) = f(0) = f(4) = 0.

f(x) =_________________________


Does anyone know how to solve this.

Since you have three roots you can start by using the model where and are the known roots of the cubic.

Then substitute f(3) = 54 and solve for .

Originally Posted by Sneaky

i have a question i have no idea how to solve.....


Find an expression for a cubic
function f if f(3) = 54 and f(-3) = f(0) = f(4) = 0.

f(x) =_________________________


Does anyone know how to solve this.

they gave you the zeros ...

f(x) = kx(x+3)(x-4) , where k is some constant

and you know f(3) = 54 ... you can find out what k is