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Hello I have question on 7.25 II-A

 
 
YangBober的头像
Hello I have question on 7.25 II-A
YangBober - 2020年07月24日 Friday 10:24
 

So I am already on this step which is x^4-10x^2+x+20=0

and I don't know how to solve it so I just uesed desmos to see what the graph looks like.

however the zero of x is like1.791 which is probably a fraction add on to a sqrt.

so can I get some help please.

 
LensmireJohn的头像
Re: Hello I have question on 7.25 II-A
LensmireJohn - 2020年07月24日 Friday 10:59
 

This problem is probably easiest using the technique we used in 7.5 from class, where we let a common number be a variable.

Here try letting $y = 5$ and see if you can solve for $y$. As in class, we need to be a little careful about what values of $x$ are possible (in the domain). The graph can help for that as well, but try to understand that algebraically as well.

Hope this helps at least get started. Let us know if you have some additional questions.

 
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