Question

Which is a factor of 8x^2 - 38x - 10

Answer 1

4
x+1
x-5
3x+1

Answer 2

i know you have to find the GCF which is 2

Answer 3

2( 4x^2 - 19x - 5)

Answer 4

yup

Answer 5

ok now we need to find two numbers that when you multiply them it equals to a*c and when you add them it equals to b
Our equation is in the form of \(ax^2+bx+c \)
so our a=4 b=-19 and c=-5
\(a*c=4*(-5)=-20 \)
So what are two numbers that when you multiply them it equals -20 and when you add them it equals -19?

Answer 6

thats what i was confused about :-/

Answer 7

lol So are u fine from here? Can u continue the rest on ur own

Answer 8

almost....

Answer 9

ok so what are the 2 numbers firstly?

Answer 10

sooooo it has to = 20x^2

Answer 11

what has to equal \( 20x^2 \)?

Answer 12

ok the 2 numbers when you multiply them have to equal -20 and when u add them it has to equal -19

Answer 13

lol i have no clue what two numbers add up to 19 and multiply to 20x^2

Answer 14

not 20x^2 its just simply -20

Answer 15

So what are two numbers that when you multiply them it equals -20 and when you add them it equals -19?

Answer 16

when you find the GCF which is 4 it would be 4(2x^2 -19x -5)

Answer 17

lol sorry

Answer 18

i ment 2 ( 4x^2 - 19 -5)

Answer 19

so wouldnt it be 20x^2

Answer 20

2(x-5)(4x+1)

Answer 21

ohhh i understand now....

Answer 22

What are your options?
2
x-5 or
4x+1
on that list?

Answer 23

Sorry abt that. My bro needed my comp emergency but ill just write out the steps neways

Answer 24

So the two numbers are 1and -20
1+(-20)=-19
1*(-20)=-20
so we now replace the -19x with 1x and -20x
\(2(4x^2+1x-20x-5)=0 \)

\( 2(x(4x+1)-5(4x+1))=0 \)
\( 2(x-5)(4x+1)=0 \)
so as we see (x-5) is the answer