SOLUTION: Find the roots of the polynomial function. f(x)=4^3-10x^2-6x =5+-1over 4 what are the roots? Am I correct so far?

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Find the roots of the polynomial function. f(x)=4^3-10x^2-6x =5+-1over 4 what are the roots? Am I correct so far?      Log On


   

Question 191781This question is from textbook saxon algebra 2
: Find the roots of the polynomial function.
f(x)=4^3-10x^2-6x
=5+-1over 4
what are the roots? Am I correct so far? This question is from textbook saxon algebra 2

Found 2 solutions by jim_thompson5910, RAY100:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
4x%5E3-10x%5E2-6x=0 First, set the right side equal to zero


2x%282x%5E2-5x-3%29=0 Factor out the GCF 2x


2x%28x-3%29%282x%2B1%29=0 Factor 2x%5E2-5x-3 to get %28x-3%29%282x%2B1%29


2x=0, x-3=0, or 2x%2B1=0 Set each factor equal to zero


x=0, x=3, or x=-1%2F2 Solve for "x" in each case


So the solutions are x=0, x=3, or x=-1%2F2

Answer by RAY100(1637) About Me  (Show Source):
You can put this solution on YOUR website!
let y= -10x^2 -6x +4^3 = -10x^2 -6x +64
at y=0, 0= -10x^2 -6x +64
0= 10x^2+6x-64
0=2(5x^2 +3x -32)
use quadratic eqn to solve
x= ( -(3) +- ( (3)^2 - 4 (5) (-32) )^1/2 ) / 2 (5)
x=( -3 +- ( 9+640)^1/2 ) /10
x=(-3 +-25.5) / 10
x=+2.25, (-2.85)
check
ok using calc