Question

I have my answer, just want to know if the discriminant is right..

y=x^2-5x-8
y=x

2 real solutions and a discriminant of 68.

Answer 1

Would the discriminant be 68 or 17?

Answer 2

@Hero

Answer 3

Would you mind showing your work ?

Answer 4

Yeah one second. I used the quadratic formula -b+-sqrt b^2 - 4ac/2a

Answer 5

Do you know what kind of problem this is you're working on?

Answer 6

Yes. I just want to know if my answer is correct

Answer 7

It says "use the discriminant to find the number of solutions for each system."

Answer 8

\[\text{ the disciminant of } y=ax^2+bx+c \text{ is } b^2-4ac\]

Answer 9

I know

Answer 10

then how did you get two solutions?

Answer 11

discriminant will only be one number

Answer 12

Because the answer it gives me is 6+-sqrt68/2 so I was wondering if the discriminant would be 68 or 17 once you simplify it.

Answer 13

so you didn't use the formula I wrote...

Answer 14

I did!!

Answer 15

b^2-4ac is going to give you the discriminant

Answer 16

then how did you get + or - for the discriminant ?

Answer 17

So it would be 68

Answer 18

D=b^2-4ac
and you have
a=1
b=-5
c=-8
just plug in
D=(-5)^2-4(1)(-8)
this shouldn't give you 68

Answer 19

Yes it should. You set the two equations equal to each other and get x^2-6x-8=0

Answer 20

I see y=x^2-5x-8

Answer 21

Why?

Answer 22

Yes, but there is also the y=x

Answer 23

because I thought the question was find the discriminant of y=x^2-5x-8? Is that not the question?

Answer 24

So once you put them equal to each other

Answer 25

Read the entire thing. It is a system. You know with the little {

Answer 26

{y=x^2-5x-8
{y=x

Answer 27

Oh I think you are trying to see how many solutions to the system there are
I didn't understand the question because the question wasn't actually given in the title

Answer 28

Yes....

Answer 29

I just wanted to know if the 68 would give me 2 real solutions

Answer 30

Is all I was asking

Answer 31

Yes replace y with x in the first equation
\[x=x^2-5x-8 \\ 0=x^2-6x-8 \\ a=1\\ b=-6 \\ c=-8 \\ D=b^2-4ac=(-6)^2-4(1)(-8)=36+32=68>0\]
yes 68>0 so that means you have two solutions

Answer 32

Thank you!

Answer 33

Is what I was saying all along, but... :/

Answer 34

It might be good to post the full question in the title next time. It would be very helpful.

Answer 35

Alright, alright.. Thank you nontheless

Answer 36

Like determine the number of solutions to the system :p

Answer 37

*nonetheless

Answer 38

and np