Question

Find all the zeroes of the poly 4x cube minus 20x cube plus 23x square plus 5x minus 6 if two of itz zeroes are 2 and 3

Answer 1

Try
(a) using symbols such as x^3 for x cube
(b) fixing your polynomial. You have two "x cube" terms.

If you meant

y = 4x^4 - 20x^3 + 23x^2 - 6

then, given roots of 2 and 3, we have

4x^4 - 20x^3 + 23x^2 - 6 is divisible by (x-2)(x-3) = x^2 - 5x + 6

A simple long division yields

(x^2 - 5x + 6)(4x^2 - 1)
or
(x-2)(x-3)(2x-1)(2x+1)

So, all the zeroes are 2, 3 , 1/2, -1/2