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Mathematics 18 Online
OpenStudy (blueyoshi):

PLEASE HELP!!! 2 Algebra questions. Will fan and medal

OpenStudy (blueyoshi):

Simplify the radical show all your steps please \sqrt{363} -3\sqrt{27}\]

OpenStudy (blueyoshi):

\[\sqrt{363}-3\sqrt{27}\]

OpenStudy (blueyoshi):

@mathmale @Kainui @samigupta8

OpenStudy (blueyoshi):

Please somebody

OpenStudy (johnweldon1993):

Okay so first, lets simplify these radicals by thinking how we can rewrite them For example \(\large \sqrt{27} = \sqrt{9 \times 3}\) We can now look at this as \[\large \sqrt{9} \sqrt{3}\] And what do we know about \(\large \sqrt{9}\) ?

OpenStudy (blueyoshi):

It's square root is 3?

OpenStudy (johnweldon1993):

Correct so we go from \[\large \sqrt{27}\] to \[\large \sqrt{9 \times 3} = \sqrt{9} \times \sqrt{3}\] to \[\large 3\sqrt{3}\] The reasoning we went through that process is because...we know 27 does not have a square root...so we need to simplify it into smaller factors that we can then work with that WILL have square roots

OpenStudy (johnweldon1993):

Let me know if that makes sense before we move on :)

OpenStudy (blueyoshi):

It does :)

OpenStudy (johnweldon1993):

Great! Okay stay with me The original problem was \[\large \sqrt{363} - 3\sqrt{27}\] What we JUST did was simplify \(\large \sqrt{27}\) into \(\large 3\sqrt{3}\) right? So I'm rewriting this to make sure we don't forget the original problem had \(\large 3\sqrt{37}\) so that answer we just found needs to be multiplied by 3 right? so we have \(\large 3\sqrt{27} = 9\sqrt{3}\) right?

OpenStudy (johnweldon1993):

Typo up there...that 37 should be 27 >.<

OpenStudy (blueyoshi):

Ok

OpenStudy (johnweldon1993):

Alright so...now we need to tackle the first radical \[\large \sqrt{363}\] What numbers *think of one we know the square root of* can be multiplied to make this number?

OpenStudy (blueyoshi):

Um...3? I do not know honestly. Also I have to leave somewhere in a couple minutes..

OpenStudy (blueyoshi):

I'm guessing 3 would be one

OpenStudy (johnweldon1993):

You are absolutely correct....3 is going to be involved...but WHAT times 3 = 363? \[\large \sqrt{363} = \sqrt{121 \times 3} = \sqrt{121} \times \sqrt{3}\] Right? well guess what? \(\large \sqrt{121} = 11\) right?

OpenStudy (blueyoshi):

Yeah!

OpenStudy (johnweldon1993):

So now we have, Altogether \[\large 11\sqrt{3} - 9\sqrt{3}\] Which we know is....?

OpenStudy (blueyoshi):

\[2\sqrt{3}\]

OpenStudy (johnweldon1993):

Exactly! :)

OpenStudy (blueyoshi):

Tysm!!! Last one, I will go ahead and fan you incase i don't get the answer immediately :( Which functions is best shown on the graph below, a. y=2sqrtx-6-1 b. y=2sqrtx+6+1 c. y=2sqrtx-6+1 d. y=2sqrtx+6-1

OpenStudy (blueyoshi):

Oh no huge typo hold on

OpenStudy (blueyoshi):

a. y=sqrt2x-6-1 b. y=sqrt2x+6+1 c. y=sqrt2x-6+1 d. y=sqrt2x+6-1

OpenStudy (blueyoshi):

sqrt as in square root as in a *insert radical sign*

OpenStudy (johnweldon1993):

Alright so it is a) \(\large y=\sqrt{2x -6} - 1\) b) \(\large y=\sqrt{2x + 6} + 1\) c) \(\large y=\sqrt{2x -6} + 1\) d) \(\large y=\sqrt{2x +6} - 1\) Right?

OpenStudy (johnweldon1993):

So here, we start with the BIG overall function and work forward Think about what the graph of \(\large y = \sqrt{x}\) looks like |dw:1462649286343:dw|

OpenStudy (blueyoshi):

Yes

OpenStudy (johnweldon1993):

Now think about what would happen if we multiplied each of those 'x' by 2 to give us the graph of \(\large y=\sqrt{2x}\) |dw:1462649389066:dw| *Still looks basically the same..just a little higher in amplitude

OpenStudy (johnweldon1993):

Now comes the parts you will SEE If we add or subtract a number from that 'x' ***NOT FROM THE WHOLE FUNCTION*** we shift the graph Left or Right Respectively Example...if I add 2 to the 'x' and I now have the graph of \(\large y = \sqrt{2x + 2}\) it would look like |dw:1462649504550:dw|

OpenStudy (johnweldon1993):

Add a number = shift to the left Subtract a number = shift to the right So HERE we can clearly see that the graph you want has been shifted to the right correct? So are we adding or subtracting 6 under the radical?

OpenStudy (blueyoshi):

substrcct

OpenStudy (johnweldon1993):

Exactly...so now, so far, we have the equation as \(\large y = \sqrt{2x - 6}\) and that looks like |dw:1462649660504:dw|

OpenStudy (johnweldon1993):

Finally, your graph has been shifted UP 1 unit...*it begins at y = 1 instead of y = 0 This vertical shift comes from adding or subtracting a number ***FROM THE FUNCTION THIS TIME*** which will shift the graph up or down respectively Adding a number = shift UP Subtracting a number = shift DOWN So are we to add or subtract the 1 from the function?

OpenStudy (blueyoshi):

add

OpenStudy (johnweldon1993):

Anddd that allows us to say the function graphed is \(\large y = \sqrt{2x - 6} + 1\)

OpenStudy (blueyoshi):

TY!!

OpenStudy (johnweldon1993):

Not a problem!

OpenStudy (kittiwitti1):

Hi! I noticed your comment on another post saying you needed help. Do you still need any or are you good? (:

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