SOLUTION: 4.6 The following function is given f(x)=x^3 -5x^2 -9x+45 a. list all rational zeros that are possible according to the Rational Zero Theorem: b.Use synthetic division to

Algebra ->  Functions -> SOLUTION: 4.6 The following function is given f(x)=x^3 -5x^2 -9x+45 a. list all rational zeros that are possible according to the Rational Zero Theorem: b.Use synthetic division to      Log On


   



Question 1013303: 4.6
The following function is given
f(x)=x^3 -5x^2 -9x+45
a. list all rational zeros that are possible according to the Rational Zero Theorem:
b.Use synthetic division to test several possible rational zeros. One raitonal zero of the given function is:
c.use the zero from part (b) to find all the zeros of the polynomial function.
The zeros of the function f(x) =x^3 -5x^2 -9x+45 are:

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
f(x)=x^3 -5x^2 -9x+45
rational zeros are +/- 1,3,5,9,15,45
1===-5====-9====45; try -3. Bring down the 1, multiply by -3 and add that to -5 to get -8. Then
1===-8------15------45 ;;;;;;;;;;;multiply that by -3 and add to -9 to get 15. Multiply that by -3 to get
(x+3) is a factor.;;;;;;;;;;;;;;;;;;;;;;;-45, and that makes 0.
(x^2-8x+15) is a factor
(x-5)(x-3)
The roots are {-3,5,3}
graph%28300%2C200%2C-10%2C10%2C-10%2C10%2Cx%5E3+-5x%5E2+-9x%2B45+%29