Polynomial root problem

[Xibu4]

I'm a bit stumped on a homework question and would greatly appreciate some input.

Does this mean that gamma is equal to 3 ? If it is how would I go about solving it because wouldn't I get
[math]\alpha \beta \gamma = -21[/math][math]\alpha +\beta +\gamma = 5[/math][math]\alpha \beta +\beta \gamma + \gamma \alpha = -1[/math]
Am I meant to solve this simultaneously ?

 

[Harry_the_cat]

Yes the root you are given is gamma. You could solve simultaneously. Just check your last equation - should your second and third terms be the same [fixed now ]?

BUT, you know that gamma is 3 and you are asked to find the sum and product of alpha and beta, NOT alpha and beta themselves. You really only need the first 2 equations.

 

[Xibu4]

Yes the root you are given is gamma. You could solve simultaneously. Just check your last equation - should your second and third terms be the same?

BUT, you know that gamma is 3 and you are asked to find the sum and product of alpha and beta, NOT alpha and beta themselves. You really only nee the first 2 equations.

Ohhh ok thank you can't believe I didn't see that.

 

[Deleted member 4993]

Ohhh ok thank you can't believe I didn't see that.

Make sure you check your answer by substituting those back into the original equation.