If two zeroes of the polynomial p(x) = 2x4 + 7x3 - 19x2- 14x + 30 are √2 and - √2 then find the other two zeroes.

Given: p(x) = 2x4 + 7x3 - 19x2- 14x + 30


Since x = √2 & - √2 is a solution so


x- √2 & x + √2 are two factors of p(x)


Multiplying the two factors we get x2-2 …Equation 1


which is also a factor of p(x)


To get the other two factors we need to perform long division


On performing long division we will get


2x2 + 7x -15 …Equation 2


Equation 2 is also a factor of p(x)


To find the other two zeroes of the polynomial we need to solve Equation 2


We use the method of factorization for solving Equation 2


2x2 + 7x -15 = 0


2x2 + 10x -3x -15 = 0


2x(x + 5) -3(x + 5) = 0


(2x-3)(x + 5) = 0


The two roots are and -5


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