Question

Factor completely: 3x^2 + 5x + 1

a. (3x + 1)(x + 1)

b. (3x + 5)(x + 1)

c. (3x − 5)(x + 1)

d. Prime

Answer 1

Didn't I just teach you?

Answer 2

Prime. It cannot be factorised.

Answer 3

Correct @ajprincess

Answer 4

I'm working on it. 3*1 = 3. 3+2 = 5.

Answer 5

But you can't do that 3 * 2 = 6!

Answer 6

Thanx @ParthKohli

Answer 7

Ohhh, I'm glad I stopped where I was then.

Answer 8

so what if b has an x?

Answer 9

If you can't factor it then it cant be factored ;P

Answer 10

like this, for example. 3x2 − x − 4.

Answer 11

3x^2 - x - 4.

Answer 12

You can factor this.

Answer 13

12

Answer 14

b = -1?

Answer 15

-12*

Answer 16

-4 * 3 = -12
-4 * 3 = -12
It can be done

Answer 17

Don't confuse it with a and b and c now. That was just a demonstration.

Answer 18

What does b = though?

Answer 19

-1

Answer 20

Just see the first and last terms and see their coefficient, multiply them.
Then split the middle term such that the split coefficients have the same product.

Answer 21

a = 3.
b = ?
c = -4.

Answer 22

b = -1

Answer 23

-x = -1x so that's very very clear

Answer 24

-4 * 3 = 12.
So, I have -1x and 12.

Answer 25

And -4 * 3 = 12
-4 + 3 = -1

:D

Answer 26

(3x − 4)(x + 1)?

Answer 27

I just don't get it.

Answer 28

Split like this.

\(\Large \color{Black}{\Rightarrow 3x^2 - 4x + 3x - 4 }\)

\(\Large \color{Black}{\Rightarrow x(3x - 4) + 1(3x - 4) }\)

\(\Large \color{Black}{\Rightarrow (x + 1)(3x - 4) }\)

Correct :D

Answer 29

Good work @ParthKohli.:)

Answer 30

Lol my smartscore is 99 I should say that to you I'm your senior ;P @ajprincess

Answer 31

I'm still confused. I just don't get it.

Answer 32

Practice with some problems. You'll get it ;p

Answer 33

I guessed on that answer. I don't get the split part and I'm still alittle confused about the part where I find sum of b and product of c. or something.. I don't know..

Answer 34

10x^2 + 2x − 8.
10 * -8 = -80.
10 - 8 = 2.
OH WOW.

Answer 35

2 = b.

Answer 36

u r right @careless850.

Answer 37

But then what do I do?

Answer 38

Don't confuse the variables in your mind. Never do that. How I learnt was just the multiplication of first and last term's coefficient and then expressing the middle term as a sum of two numbers that have their product equal the multiplication of first and last coefficients.

Answer 39

Hm. So what do I do now? Because I have to turn them into the factorization.

Answer 40

See the first two and last two terms. Factorize them and then group them. See what I have done in the answer very carefully.

Answer 41

out of the options. --> 2(5x − 1)(x + 4)

2(5x − 4)(x + 1)

2(5x + 2)(x − 2)

2(5x − 2)(x + 2).

which one could I eliminate right off the start?

Answer 42

Lol if you have options, you can multiply all and check :P no need to learn factorization hehe

Answer 43

I looked at the one you did earlier.
Well, my next question don't have options.

Answer 44

And I don't see why you put the x infront of the (3x-4)

Answer 45

on the 2nd part.

Answer 46

Then see my method again and again until you get it....or see khanacademy.

Answer 47

http://www.youtube.com/watch?v=X7B_tH4O-_s

Answer 48

first u can take 2 out from the expression 10x^2 + 2x − 8 bcos 2 is common to all 10, 2 and 8. Is it clear?