Question

Multiply the following expressions and simplify: (3x – 1)(2x + 5)

Answer 1

Do you know how to do the FOIL method?

Answer 2

no :/

Answer 3

http://www.google.com/imgres?imgurl=http://www.mathsisfun.com/algebra/images/foil.gif&imgrefurl=http://www.mathsisfun.com/definitions/foil-method.html&h=140&w=250&sz=4&tbnid=k-FYdyDkz9olqM:&tbnh=67&tbnw=120&zoom=1&usg=__Zz-ZRFrbarnu0cs1ve2Pbc-ruj0=&docid=8cPukqnR8LhHOM&sa=X&ei=rAPmUaSGNZjH4AOR7YHoBw&ved=0CFEQ9QEwBA&dur=784 Do you understand now?

Answer 4

So you do "first" first. So what does 3x * 2x give us?

Answer 5

9x

Answer 6

Hmm. 3 * 2 would give us?

Answer 7

6x

Answer 8

x * x would give us?

Answer 9

2x

Answer 10

Pretend x was 10.
Would would 10 * 10 give us?

Answer 11

100

Answer 12

What is another way of saying 100?

Answer 13

By using 10?

Answer 14

i dont know ._.

Answer 15

TIP: Use exponent. Does it ring a bell?

Answer 16

haivenn, what does 10^2 give us?

Answer 17

100

Answer 18

Great. So if 10 * 10 = 10^2
What would x * x give us?

Answer 19

x^2

Answer 20

Good. Now do outer. What does:
3x * 5 give us?

Answer 21

15x

Answer 22

Good. Now do the inner.
What does -1 * 2x give us?

Answer 23

-2x

Answer 24

Great. Final step is to do the Last.
What does -1 * 5 give us?

Answer 25

-5x

Answer 26

Hold! Where did you get that x from?

Answer 27

i meant -5 aha sorry

Answer 28

Great!
So now we'll get 6x^2 + 15x - 2x - 5
Do you understand it so far?

Answer 29

yes (:

Answer 30

Alright. Now we need to simplify it by combining like terms.
Which terms can we combine?

Answer 31

15x and -2x

Answer 32

Great! What does that give us after combining?

Answer 33

13x

Answer 34

Great! So now you have 6x^2 + 13x - 5.
Can we simplify any more?

Answer 35

no not that i see

Answer 36

Great! So that's your answer.
I hope this help! :)
Do you know how to do the FOIL method now?

Answer 37

yes thank you (:!

Answer 38

Good to hear! If you think I helped you a lot, press the blue Best Response button on the right side. :)