Question

what are the factors of the expression X^2+X-20 @precal

Answer 1

ok look at your last number 20

Answer 2

list all the factors of 20
(?) times (?)

Answer 3

hint 1 times 20 can you think of others?

Answer 4

1•20
2•10
4•5

Answer 5

yes good job, now let's look at the sign in front of 20 what is it?

Answer 6

negative

Answer 7

or minus

Answer 8

yes and that sign will tell us to subtract the factors, we only want positive numbers so
20-1 =19 we don't want 1-20=-19
can you subtract the other two?

Answer 9

would that mean they both have to be negative

Answer 10

no, both have to be positive

Answer 11

20-1=?
10-2=?
5-4=?

Answer 12

now keep in mind, if we can factor this, our middle number will appear

Answer 13

so could you solve it

Answer 14

no, I am teaching you how to solve it
ever heard of "teach a man to fish, he eats forever,
give a man a fish, he eats for one day"
You are learning to fish, my friend.......

Answer 15

ok so tell me
20-1=19
5-4=what number
10-2 =what number

Answer 16

10-2

Answer 17

10-2=8
5-4=1
what is your middle term?

Answer 18

Ohhh its 5-4 because there is an invisible 1 in front of the x

Answer 19

+1x yes that is correct

Answer 20

now we need to figure out our signs

Answer 21

a negative sign can only happen if you multiply (+)(-) so we have to figure out the signs of 5 and 4
do we want -5+4
or do we want +5-4
keep in mind we need +1x

Answer 22

we are almost done, hang in there

Answer 23

+5-4

Answer 24

yes so the answer is
(x+5)(x-4)

Answer 25

if you were to multiply this out you would get your original equation

Answer 26

so then how would i write it in my paper

Answer 27

The factors are (x+5)(x-4)

Answer 28

just like we did it, I like to show my table of factors

Answer 29

Because i want to show my work

Answer 30

well how does your teacher teach factoring, there are many ways teachers teach factoring

Answer 31

the usual way a teacher should do it

Answer 32

there really is not one way to teach factoring, teachers pick whichever style of doing it. I just showed you my style of factoring

Answer 33

so how can i write in my paper so that i can show work to it