Question

Solve 2x^3+7x^2-2x-1=o​

Answer 1

Answer:

$x=\sqrt{3}-2\\x=-\sqrt{3}-2\\x=\frac{1}{2}$

Step-by-step explanation:

This is a hard one

We have to use the rational root theorem

$2x^3+7x^2-2x-1$ = 0

We have to find all the factors of a and d and put them in a fraction

$a=2\\d=-1\\\frac{1}{1,2}$

We then plug them into the equation to see if any of them work

The equation isn't true when plugging 1, but is true when plugging in 1/2

factored form of 1/2 is (2x-1)

Then we divide the original equation by (2x-1) (you can use synthetic division or long division, it would be hard to type out the process for that) to get $x^2+4x+1$

So now the equation is $(2x-1)(x^2+4x+1)$

Solve the second half of this equation using the quadratic formula to get

$\sqrt{3}-2$ and $-\sqrt{3}-2$

We already know the solution for the first half of the equation (1/2)

So the final answers are:

$x=\sqrt{3}-2, -\sqrt{3}-2, \frac{1}{2}$