Question

3x^2y^2 - 75 can someone help me they said to also use F.O.I.L

Answer 1

i don't know who the "they" is, but they are dead wrong
first off, there is no such thing as foil
secondly your job it to factor, not multiply out

Answer 2

start with
\[3(x^2y^2-25)\] then factor the \(x^2y^2-25\) part as the difference of two squares
\[a^2-b^2=(a+b)(a-b)\] with \(a=xy,b=5\)

Answer 3

they told me i could use foil but plzzz can you help me :(

Answer 4

they are full of crap

Answer 5

lol ikw right

Answer 6

did you understand what i wrote above?

Answer 7

kinda im sorry im just trying to finish this thing they keep pressuring me about it and i dont understand it sorry

Answer 8

start with
\[3x^2y^2-75\] both terms have a common factor of \(3\) so "factor it out" and get
\[3(x^2y^2-25)\]

Answer 9

then factor the \((x^2y^2-25)\) piece as the difference of two squares \((a+b)(a-b)\) with \(a=xy, b=5\)

Answer 10

this will give you
\[3(xy+5)(xy-5)\]

Answer 11

is there really a "they"?

Answer 12

yeah my online teachers

Answer 13

if your on line teacher said "foil" they should be banned from teaching

Answer 14

can you help me with more plzzz :/ ill give u medals i promise

Answer 15

and this is not multiplying, it is factoring

Answer 16

lol right i dont thing they know wat they doing

Answer 17

i will be happy to help
as for the medals, i have plenty

Answer 18

i know they don't

Answer 19

lol okay but i would love to make u have more its not a bother to me

Answer 20

go ahead and ask

Answer 21

ok 2x^3 + 54

Answer 22

factor? first factor out the 2 and get
\[2(x^3+27)\] then you have the "sum of two cubes" which factors as
\[a^3+b^3=(a-b)(a^2-ab+b^2)\] in your case \(a=x,b=3\) giving you
\[2(x+3)(x^2-3x+9)\]

Answer 23

sorry middle line is wrong, it is \(a^3+b^3=(a+b)(a^2-ab+b^2)\)
answer is correct though

Answer 24

oh okay lol but i have more if you dont mind :/ im sorry

Answer 25

you have me for ten more minutes
go ahead and ask

Answer 26

ok

Answer 27

3. 2x^2 - 11x - 40

Answer 28

ok i hate factoring, but we can do it

Answer 29

okay:)

Answer 30

i hope you don't have to explain how to do it, do you?
answer is
\[(x-8)(2x+5)\]

Answer 31

no

Answer 32

ok then let me show you how to cheat
http://www.wolframalpha.com/input/?i=2x^2+-+11x+-+40+

Answer 33

next...

Answer 34

5. x^2 – x – 42

Answer 35

omg they give u everything thankkkk you :O

Answer 36

this one is easier
since \(-7\times 6=-42\) and \(-7+6=-1\) your answer is
\[(x-7)(x+6)\]

Answer 37

lol easy right?

Answer 38

lol yeah

Answer 39

of course it doesn't explain much
any more?

Answer 40

really

Answer 41

2x^2 – 20x + 40

Answer 42

factor out the 2 and get
\[2(x^2-10x+20)\]

Answer 43

that is the best you can do, because \(x^2-10x+20\) does not factor using integers

Answer 44

yeah i kinda saw that 2 lol

Answer 45

that is really all you can do for this one

Answer 46

any more?

Answer 47

6. 21x^2 + 31x + 4

Answer 48

7. 3x^3 + 27

Answer 49

\[(3 x+4) (7 x+1)\]for the first one

Answer 50

8. x^2 + 9x + 20

Answer 51

second one it is really \(3x^3+27\)? only can factor out a 3 and get \(3(x^3+9)\)

Answer 52

as for number 8, see if you can do it yourself
if you cannot, paste it in to wolfram and see what you get

Answer 53

0h okay np

Answer 54

for \(x^2 + 9x + 20\) see if you can think up two numbers that if you multiply them you get 20, and if you add them you get 9

it should be pretty easy here

Answer 55

with a tiny bit of practice you will come up with \(4\) and \(5\)right away, since \(4\times 5=20\) adn \(4+5=9\)

Answer 56

this means
\[x^2+9x+20=(x+4)(x+5)\]

Answer 57

oh ok

Answer 58

any more?

Answer 59

yeah i have one last one but it looks diffrent

Answer 60

okay lets take a look?

Answer 61

3rs - 2r - 3s + 2

Answer 62

summer on line class?

Answer 63

yeah its killing me

Answer 64

must be punishment for failing in the spring huh?

Answer 65

yeah i had a really crappy teacher and i didnt learn much

Answer 66

\[3rs - 2r - 3s + 2\]\[=r(3x-1)-1(3s-2)=(r-1)(3s-2)\] this is called "factor by grouping"
mostly i don't believe it when people say they failed because of a crappy teacher, but if your teacher say "foil" i believe you
good luck!
done?

Answer 67

awww thanks :) and yes i am thank you sooo much ill message u wen i need anything else :)

Answer 68

you can always come back and post when you need help

Answer 69

ok :)