Find all rational zeros of the polynomial Px 6x4 7x3 13x2
Find all rational zeros of the polynomial
P(x) = 6x4 7x3 13x2 + 4x + 4
write the polynomial in factored form
Solution
Solution:
Given
P(x) = 6x4 7x3 13x3 + 4x + 4
As we can see that for x = -1
we get p(-1) = 0
so the x+1 is factor of P(x)
thus we can write
P(x)= (x+10) (6x3 -13x2 +4)
As we again factorise
(6x3 -13x2 +4)
for x = 2
we get
(6x3 -13x2 +4) = 0
therefore x -2 is factor of (6x3 -13x2 +4)
therefore (6x3 -13x2 +4) = (x-2) (6x2 -x -2)
again
(6x2 -x -2) can be written as (2x+1) (3x-2)
So from above
P(x) = 6x4 7x3 13x3 + 4x + 4
can be written in factored form
P(x) = (x+1) (x-2) (2x+1) (3x-2)
Now
all rational zeros of the polynomials
are x = -1 , 2 , -1/2 and 2/3
Answer
