Question

help please :]
(6+3√2)(5-√2) ??



answers: 24+21√2
24+9√2
30+6√2
30+11√2

Answer 1

Try using FOIL, what happens?

Answer 2

i dont know how to use it on this.

Answer 3

It's similar.

Answer 4

Start with First. What do you get?

Answer 5

try
1/6 [ (6+3√2)(5-√2)] multiply by reciprocal of 6

Answer 6

simplifies to

3√2( 5-√2/6)

Answer 7

can you finish the rest?

Answer 8

keep in mind that √x * √x = x

Answer 9

Then do outer: 6* -√2 and inner: 3√2 *5. add the like terms together.

Answer 10

doh i was going to let skate try :P

Answer 11

I'm not finishing it for him :P but I do remember radicals giving me trouble

Answer 12

so ur adding 6 and-√2 together? im sorry im new at this and its freaking hard haha

Answer 13

no

Answer 14

dam

Answer 15

so i will go over this again

Answer 16

you have this

(6+3√2) (5-√2) <-------- this is given

Answer 17

yes

Answer 18

simplify


1/6 [ 6+3√2)(5-√2) ] multiply the whole equation by reciprocal of 6
^
L____________ this is the reciprocal of 6 (it is 1/6)

the number multiplied by its reciprocal will always = 1 , x * 1/x = 1 and -x * -1/x =1

Answer 19

...I disagree, mth3v4. You can't divide the entire problem by 6. It's in the parentheses. If there were multiples of 6 in each term, then you could.

Answer 20

mmmm okies

Answer 21

you got a point

Answer 22

careless mistake xD

Answer 23

No worries, we've all done that :)

Answer 24

OK, Skate, you have experience doing FOIL, right?

Answer 25

yes

Answer 26

but can you factor the 6 out?

Answer 27

Ok, so which terms are first, outer, inner, and last?

Answer 28

Wait no u still get a 1 :P

Answer 29

No, you can't.

Answer 30

nm i didnt say nething

Answer 31

You aren't factoring this problem, it's already factored.

Answer 32

So, skate, what are the first terms?

Answer 33

i was just saying factor out a 6 of the first parenthesis ( but you end w/ a 1+3√2< not what i want)

Answer 34

6?

Answer 35

that's the first term in the first parentheses. What's the one in the second set?

Answer 36

5

Answer 37

ok, so multiply those two together. What do you get?

Answer 38

30

Answer 39

nice job! OK, so that's first. Now, what are the two outer terms?

Answer 40

√2 and -√2 right?

Answer 41

no, those are the Last terms, but we can do that now if you'd like

Answer 42

Remember to keep the 3 in there though.

Answer 43

ok

Answer 44

ohh alright

Answer 45

well you can have a fun way to do FOIL :D

first inner outer last but

_____________ |
|-----|----------| |
( 1x + 1y ) ( 2x + 2y )
\ L_______/ /
\________________/



an easier(fun way to do FOIL (i prefer)
make a happy face :)

Answer 46

I like the happy face way!!

Answer 47

teacher taught me not my credit

Answer 48

So what do you get when you multiply the outer terms?

Answer 49

its easier to keep track of what im doing

Answer 50

you multiply 3 and -2 or 3 and √2? and thanks for the happy face foil method haha :]

Answer 51

lol

Answer 52

fun to be happy

Answer 53

yup especially in math lol xP

Answer 54

math is cool (when your good at it) xD

Answer 55

for the last terms, you're right, it becomes 3 times -2

Answer 56

ok so -6

Answer 57

ok, so add -6 to 30. what do you get?

Answer 58

24

Answer 59

?

Answer 60

yep! So that narrows it down to two.

Answer 61

Now, what are the outer terms and the inner terms?

Answer 62

wait lemme check again

Answer 63

i think what we are dealing with here is conjugate multiplication right?

Answer 64

umm? im really not sure :p

Answer 65

sorry

Answer 66

I don't actually know, sorry.

Answer 67

ya its conjugate factored difference of squares

Answer 68

Ok, skate, what are the outer terms?

Answer 69

24? or is it 30?

Answer 70

you got difference of squares with 3 √2, √2

Answer 71

you already added the first and last terms together, and got 24

Answer 72

its the squareroot

Answer 73

we're trying to get the second part of the answer, which you need the outer and inner terms for

Answer 74

√x *√ x = x

Answer 75

um. that's what we did for the last terms. but that's not in the outer and inner terms.

Answer 76

ok

Answer 77

Skate, using the happy face method that mth3v4 showed you, what are the outer terms? and then multiply them together.

Answer 78

ohh so 2 and -2?

Answer 79

wait never mind thats wrong

Answer 80

so no more radical
its just 30-3

Answer 81

right?

Answer 82

No.

Answer 83

Ok, so the outer terms are 6 and -√2. Multiply them together

Answer 84

-12

Answer 85

its a difference of squares problem (1-√x^2)(1+√x^2) , (1 + x^2) (1- x^2)

right?

or is it another careless mistake :P (i actually make a lot of them, really )

Answer 86

hah i knew it

Answer 87

@Skate: not exactly. Replace √2 with x. What's 6 * x?

Answer 88

@mth3v4: no, it's not a difference of squares problem

Answer 89

okies i got 24

Answer 90

6x?

Answer 91

yep! so that makes it 6√2, right?

Answer 92

so now the inner terms. can you find them?

Answer 93

but i still think this is very much in the form a diff squares prob reasons because

the expression was in the form of this

(n + √x) (n-√x) n= whatever number

Answer 94

diff of squares.

(x+1)(x-1)= x^2

Answer 95

radical √x *√x = x

Answer 96

It is in the form of a difference of square problem in that one is positive and one is negative, but it doesn't fall under the definition of a difference of squares. Because there are no squares.

Answer 97

OK, skate, inner terms are 3√2 * 5. multiply together, k?

Answer 98

ok