Question

divide and rationalize 3+sqrt(18)/ 1+sqrt(8)

Answer 1

hey, how's it going?

Answer 2

hi can you help me?

Answer 3

sure, first do you know how to simplify sqrt(18) and sqrt(8)?

Answer 4

yes i simplified the problem to \[3+3\sqrt{2}/1+2\sqrt{2}\]

Answer 5

good!

Answer 6

when you have a square root in the denominator, to clean it up you have to multiply by something called the conjugate, which basically just means you change the sign of the square root term

Answer 7

i did that too.

Answer 8

so for this case, you would multiply it by (1-2sqrt(2))/(1-2(sqrt(2))

Answer 9

\[1-2\sqrt{2}\] right?

Answer 10

right, so did you multiply the top and bottom by that?

Answer 11

i did but i erased it.

Answer 12

but just foil right? i get the top part but the bottom confuses me.

Answer 13

what confuses you about the bottom part? what did you get for the top?

Answer 14

i got \[3-6\sqrt{2}+6\sqrt{2}-12\] simplified to -9

Answer 15

WHat hold on somyjing looks rwong

Answer 16

thats what i figured i got everything till the foiling part

Answer 17

bob how did you do this

Answer 18

2sqrt(2)*3sqrt(2) is what?

Answer 19

\[6\sqrt{2}\]

Answer 20

well no, that is 12, but you got that part right, your mistake was 3sqrt(2) * 1 i believe

Answer 21

oh your right... i thought i was going to be able to eliminate the roots in the middle...

Answer 22

you want to eliminate the roots on the bottom, that's why are we doing this. you don't have to eliminate the roots on the top.

Answer 23

\[3-6\sqrt{2}+3\sqrt{2}\] -12 right?

Answer 24

looks good for the top

Answer 25

i kept getting 1-8

Answer 26

looks good, so what's your end answer?

Answer 27

hold on i haven't solved it yet, thought you were going to say i was wrong.

Answer 28

where's your confidence? :)

Answer 29

not in my math capabilities thats for sure haha. \[-9-3\sqrt{2}/-7\]

Answer 30

okay so the numbers are right but my text book says all the nubmer are positive.

Answer 31

looks good, don't forget parentheses if you write it like you typed it, and you can multiply by -1/-1 and get rid of all the negatives if you want

Answer 32

parentheses? the ones used to foil? and okay thank you soo much your very helpful.

Answer 33

i was just saying the way you typed your answer, could be -9 - (3sqrt(2)/-7) which is not the same thing