posted by Trina .
Use the discriminant to find out whether this quadratic polynomial can be factored. Factor the polynomial if it is not prime. This polnomial is prime, so I cannot factor it. I just need help with the discriminant part. Thaks in advance for your help.
The discriminant is b^2 - 4 ac = 729 -720 = 9. Since the square root of that is an integer (3), the polynomial can be factored.
The roots are (1/8)[27 +/-3] = 30/8 and 3
4x^2-27x+45 = (x-3)(4x- 15) are the factors