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OpenStudy (anonymous):

help :)

OpenStudy (anonymous):

Find the solution of \[\sqrt{x + 3 + 6} = 9 \] and determine if it is an extraneous solution. x = 0; extraneous x = 0; not extraneous x = 6; extraneous x = 6; not extraneous

OpenStudy (anonymous):

@freckles

OpenStudy (freckles):

is that 6 really underneath the square root?

OpenStudy (anonymous):

no

OpenStudy (freckles):

\[\sqrt{x+3}+6=9\] so you mean this?

OpenStudy (freckles):

First step subtract 6 on both sides. After that square to get rid of the square root.

OpenStudy (freckles):

\[\sqrt{x+3}=9-6\] square both sides after simplifying the right hand side

OpenStudy (anonymous):

yup and im not good at sqrt...

OpenStudy (freckles):

do you know how to square both sides?

OpenStudy (anonymous):

no

OpenStudy (freckles):

(sqrt(x+3))^2 is just equal to x+3 that is why we are squaring both sides

OpenStudy (freckles):

\[(\sqrt{x+3})^2=(9-6)^2\] \[x+3=(9-6)^2\] see if you finish solving this

OpenStudy (anonymous):

x + 3 = 9 - 3 - 3 x = 6?

OpenStudy (freckles):

yes now check the solution if x=6 doesn't work then the solution is not really a solution and consider an extraneous solution if x=6 does work then the solution is not extraneous

OpenStudy (freckles):

\[\sqrt{x+3}+6=9\] replace x with 6

OpenStudy (anonymous):

so i plug in 6 into the original equation?

OpenStudy (anonymous):

okay give me a sec

OpenStudy (anonymous):

i got 9 = 9

OpenStudy (freckles):

9=9 is totally true

OpenStudy (freckles):

because 9 is in fact 9

OpenStudy (freckles):

so that means the solution works

OpenStudy (freckles):

and according to my if then statements the x=6 in non-extran

OpenStudy (anonymous):

yeap so it will be if x= 6 not extraneous

OpenStudy (freckles):

yep

OpenStudy (anonymous):

k thnx your really good at explaining is it okay if you help me with more?

OpenStudy (freckles):

so here is another one: \[\sqrt{x-3}=10 \\ \text{ \square both sides to get rid of the square root } \\ x-3=10^2 \\ x-3=100 \\ x=103 \\ \] and then you can check it this showing you another with a square root

OpenStudy (freckles):

\[(\sqrt{x})^2=x\]

OpenStudy (freckles):

the square on the outside will just cancel the square root thing inside

OpenStudy (anonymous):

should I plug in the 103 into the original equation and solve for the one you made?

OpenStudy (freckles):

sure to determine if it is extran or non-extran

OpenStudy (anonymous):

it is not extran because 10 = 10 so for this the answer would be x = 103 non extran

OpenStudy (freckles):

yes you will end up with 10=10 which is a true statement so x=103 is non-extran ----- I think I can help with one more question then I eat pizza

OpenStudy (anonymous):

lol okay but it's a little different should i open it in new tab?

OpenStudy (freckles):

I can think of one that will give you extran \[\sqrt{x-2}=-11 \\ x-2=(-11)^2 \\ x-2=121 \\ x=121+2 \\ x=123 \\ \text{ \check } \sqrt{123-2}= \sqrt{121}=11 \neq -11 \text{ so since } 11 \neq -11 \\ x=123 \text{ is extran }\]

OpenStudy (freckles):

open a new tab just in case I have to go

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