SOLUTION: Please help me find all the zeros of the function by the root theorem! 2x^3 - 4x^2 - 10x + 20 = 0

Algebra ->  Rational-functions -> SOLUTION: Please help me find all the zeros of the function by the root theorem! 2x^3 - 4x^2 - 10x + 20 = 0       Log On


   



Question 818163: Please help me find all the zeros of the function by the root theorem! 2x^3 - 4x^2 - 10x + 20 = 0
Answer by dkppathak(439) About Me  (Show Source):
You can put this solution on YOUR website!
find all the zeros of the function by the root theorem! 2x^3 - 4x^2 - 10x + 20=0
2x^3 - 4x^2 - 10x + 20 = 0
by putting x=2
we will get value of polynomial as 0
so (x-2) is one factor by remainder theorem
by dividing whole polynomial by x-2
we will get
2x^3 - 4x^2 - 10x + 20 /x-2=2x^2-10
so factors are (x-2)(2X^2-10)=0
x-2=0 or 2x^2-10=0
x=2 or 2x^2=10
or x^2=5
or x=sqrt 5
therefor zero of equations are ( as we know zero of cubic equations will be 3)
x=2 or x=sqrt5 or x=-sqrt5