Question

how do is solve this
13x^2-38x-3

Answer 1

Do you mean how to factor it?

Answer 2

yes

Answer 3

(13x+1)(x-3)

Answer 4

how

Answer 5

Do you know that trinomials come from multiplying two binomials?

Answer 6

yes

Answer 7

So we know it would be ( )( )

Answer 8

yes i get that

Answer 9

We also know that one sign would have to be positive and one negative since the last term is negative. Still with me?

Answer 10

yes agree

Answer 11

Now how could we possibly get 13x^2 ?

Answer 12

what do u mean?

Answer 13

you can do this by grouping with the ac method:
ax^2+bx+c
a=13
c=-3
ac=-39x^2
Find two factors of -39 that add up to -38
The factors are -39x and +1x

To group, rewrite the equation
13x^2-39x+1x-3
remove like variables
13x(x-3)+1(x-3)
remove (x-3) as a factor and combine 13x+1:
(x-3)(13x+1)

Answer 14

The first term of the trinomial we are trying to factor is 13x^2. So we have to multiply 2 factors that will give us 13x^2 . What might they be?

Answer 15

Oh. I see that rickjbr wants to help you now so I'll turn you over to him.

Answer 16

1*13

Answer 17

sorry mertsj

Answer 18

didn't mean to jump in

Answer 19

so who's going to help me?

Answer 20

i'll help

Answer 21

ok so i don't understand why it is (x-3)(13x+1)

Answer 22

if you expand those two binomials, youll get back to your original trinomial using the FOIL method

Answer 23

13x^2+1x-39x-3=
13x^2-38x-3

Answer 24

oh i got it i was just confusing myself

Answer 25

thank you!!!

Answer 26

sure no problem