Question

I really need help with all of those questions:

1) 3√18 + 5√50

2) 3√8 - √32 + 3√72 - √75

3)1/√7

4)√2/√5

I am having a hard time with this lesson can you please explain how to do each one of those? thank you

Answer 1

yeah but i have to wrote how i got the answer

Answer 2

\[3\sqrt{18}\] is the same as three times the square root of 18, treat each part containing a radical the same way.

Answer 3

18 does not have a square root, so we have to break it down until we find a number that has a nice looking square root. 9 and 2 multiply to make 18, and the square root of 9 is three, so we can write the first part of problem one as \[3\sqrt{2}\], because the square root of nine is three, so it can come out, and the two left over remains under the radical.

Answer 4

Um , i think that it can't be \[3\sqrt{2}\] its \[9\sqrt{2}\]

Answer 5

oh thnx

Answer 6

You sure, Mimi?

and for the second part of that problem, fifty breaks down into 2 * 25, and the square root of 25 is 5, so the five comes out, and it looks like \[5\sqrt{2}\]. Notice how the numbers under the radicals are the same? These are called like bases, so now all you have to do is add the 3 and the 5, and your final answer should be \[8\sqrt{2}\] for problem one

Answer 7

ok i got that what about number 2?

Answer 8

same deal, break it down and do the arithmetic.

Answer 9

eh its kind of more confusing

Answer 10

I can give you a tip, the eight under the radical in part one looks like a solid base for a like term, so see what factors of eight you can find to square root and pull out.

Answer 11

Yup im sure , super
because when you \[3\sqrt{2}\] in the calculator its 4.24..... that doesn't equal to \[3\sqrt{18}\] but when you put \[9\sqrt{2}\] it equals to 12.727... that is the same as \[3\sqrt{18}\]
Normally , wouldn't be sure but this time I am xD

Answer 12

I have to disagree, nine can not be the square root of nine, it appears you are just shifting it out from under the radical.

Answer 13

However, I did just catch an error I made, Multiply the three you pulled out with the three already there, and our answers match.

Answer 14

Well, idk what radical means but try it in your calculator and you will see . but then the 9 is outside the square root so you don't sqaure root it again.
So i was right , right ?

Answer 15

right, but remember, you pulled out a three from under the radical, and then multiplied it to the three outside. A nine did not come from the radical, because the answer would be 27 times the square root of two. A radical is the "house" the 18 lives in.

Answer 16

LOL, the 'house' ok , i learnt a new thing today xD , isn't that a square root then ?

Answer 17

oh ok thnx ^_^