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Mathematics 17 Online
OpenStudy (anonymous):

question in comments with correct math format

OpenStudy (anonymous):

\[3\sqrt{2x-3}+2\sqrt{7-x}=11\]

OpenStudy (unklerhaukus):

square both sides

OpenStudy (anonymous):

so it would be: 3(2x-3)^2+2(7-x)^2=11^2

OpenStudy (anonymous):

whats after that? I am trying to check answers

OpenStudy (unklerhaukus):

actually this problem isn't as straight forward as i first thought

OpenStudy (anonymous):

oh i was wondering why I was super wrong.

OpenStudy (anonymous):

It is actually easier to bring one of the terms with the radical to the RHS to make expansion of squares easier.

OpenStudy (anonymous):

And doing so makes it straight forward :)

OpenStudy (anonymous):

would you mind showing me what you mean?

OpenStudy (anonymous):

\[3\sqrt{2x-3}=11-2\sqrt{7-x}\]

OpenStudy (anonymous):

\[(3\sqrt{2x-3})^2=(11-2\sqrt{7-x})^2\] You have to isolate one of the radicals in an equation with multiple radicals

OpenStudy (anonymous):

Then you expand (x-y)^2=x^2-2xy+y^2

OpenStudy (anonymous):

And also, it is of important note to remember that square root and square are opposite operations and so they cancel

OpenStudy (anonymous):

so where did you get the x and y?

OpenStudy (anonymous):

so \[9(2x-3)=121-44\sqrt{7-x}+4(7-x)\]

OpenStudy (anonymous):

That is just to show you/remind you how to expand a polynomial.

OpenStudy (anonymous):

oh gotcha!

OpenStudy (anonymous):

:) Do you know where to go from there? and you would have to isolate your radical again.

OpenStudy (theviper):

\[(3\sqrt{2x-3}+2\sqrt{7-x})^2=11^2\]

OpenStudy (theviper):

Do that:) Remember \[(a+b)^2=a^2+b^2+2ab\]

OpenStudy (anonymous):

yes thanks guys!

OpenStudy (theviper):

yw:)

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