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Mathematics 8 Online
OpenStudy (anonymous):

help please

OpenStudy (anonymous):

OpenStudy (anonymous):

@johnweldon1993

OpenStudy (johnweldon1993):

Okay ...our first step...is to divide both sides by 3...because we want to get that cubed root by itself on the left side...so we can do the same trick we did in the last problem... So dividing both sides by 3 we have \[\large \sqrt[3]{x^2} = 9\] Right?

OpenStudy (anonymous):

yes

OpenStudy (johnweldon1993):

\[\large \frac{ = 3\sqrt[3]{x^2}=27}{3} => \sqrt[3]{x^2} = 9\] So now...we do the trick we did last time

OpenStudy (anonymous):

whats that?

OpenStudy (johnweldon1993):

It was just me writing out as an equation of what dividing by 3 looks like :) exactly what I said above (just done visually)

OpenStudy (anonymous):

so now what

OpenStudy (johnweldon1993):

So now...we have the cubed root alone on the left side of the equation...just like that last question...So in order to cancel out a cubed root...we raise it to the 3rd power.......just like to get rid of a square root we would raise to the 2nd power...and a 4th root we would raise to the 4th etc...

OpenStudy (anonymous):

so confused haha..

OpenStudy (johnweldon1993):

So to cancel that out....we raise this all to the 3rd power....this will cancel out that cued root.... \[\large (\sqrt[3]{x^2})^3 = 9^3\] This becomes \[\large x^2 = 9^3\] And 9^3 is just 9x9x9 = 729 So \[\large x^2 = 729\] Now what?

OpenStudy (anonymous):

would u divied it by 2 hahha just a guess

OpenStudy (johnweldon1993):

Well let me clarify first...I think what you're getting confused on is the roots and powers thing...so hang on

OpenStudy (johnweldon1993):

\[\huge (\sqrt[\cancel{2}]{x^2})^\cancel{2} = x^2\] \[\huge (\sqrt[\cancel{3}]{x^2})^\cancel{3} = x^2\] \[\huge (\sqrt[\cancel{4}]{x^2})^\cancel{4} = x^2\] Make sense? when you raise a root...to its power you cancel it...raising a cubed (2) root to the 2nd power...cancels it

OpenStudy (anonymous):

ok yah i think it does now

OpenStudy (johnweldon1993):

Okay so above again...all we did was raise the cubed root to the third power so it canceled... \[\huge (\sqrt[\cancel{3}]{x^2})^\cancel{3} = 9^3\] Which is now \[\huge x^2 = 729\] Okay ready for the last step?

OpenStudy (anonymous):

x = 27?

OpenStudy (johnweldon1993):

Beat me to it :) Yeah that's your answer

OpenStudy (anonymous):

hahah thank you :)

OpenStudy (johnweldon1993):

Anytime!

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