What kind of equation is this? I don't get it

[onemind]

Hi,

I have never really been a math type of person and am taking a intro to math course at uni.

I am asked to solve an equation in the same format as the one below and indicate clearly the method used.

The trouble is I have no idea how to do it

 

[math]

{6}/{y} + {8}/{y^2} = -1

[/math]

 

I would really appreciated any help.

Thanks

 

edit: I don't know how to make fractions with latex

[Callipygous]

multiply everything by y^2

 

 

( i dont know how to use latex at all : P )

[onemind]

Thanks Callipygous

Great help

[onemind]

Hi again.

I thought I had it figured out but I am confused again

When I multiply it by y^2 I get

[math]

6y+8=-y^2

[/math]

then i set the right hand side to 0 to get

[math]

y^2+6y+8=0

[/math]

this is general quadratic form isn't it?

So I plug the coefficients into the quadratic formula and get

-2, -4

 

What are these numbers?

If I put them into the original quadratic form i get

-7,-3.5

I don't get it

Thanks again

[Callipygous]

-2 and -4 are the two solutions for y.

 

im confused about how you got -7 and - 3.5

 

when i plug -2 into the y's in the first equation it turns it into -1=-1

 

i just checked -4, same thing

[onemind]

hi again

when i type [math]6/-2+8/-2^2[/math]

into my calculator it gives me -5

by hand i get 6/-2= -3 8/-2^2 = -2

so -3+(-2)= -5

 

What am I doing wrong?

[Callipygous]

hi again

when i type [math]6/-2+8/-2^2[/math]

into my calculator it gives me -5

by hand i get 6/-2= -3 8/-2^2 = -2

so -3+(-2)= -5

 

What am I doing wrong?

 

 

when you type it into your calc you are probably getting an order of operations problem. put parentheses around the right stuff and it should work.

 

as for by hand:

 

6/-2= -3 but -2^2= 4, not negative 4. so 8/-2^2= 2 not -2

 

-3 + 2 = -1

[onemind]

excellent

I knew -2^2 was 4 but my ti82 calculator said it was -4

I didn't think it could get something so simple wrong

Thanks heaps

[ku]

Be careful with this:

 

[math]-2^{2}=-4[/math] but [math](-2)^{2}=4[/math].

[onemind]

Thanks Ku,

I think I'll just be content to know that I will never really understand math

[ku]

I exprienced this same problem when I was a little boy. Just remember that when you type -2^2 in your calculator, the calculator interprets it as [math]-(2^2)[/math] and not [math](-2)^2[/math].

 

[math]-(2^2) = -(4) = -4[/math]

 

[math](-2)^2 = -2 \times -2 = 4[/math] (remember that negative times negative equals a positive)

[onemind]

Ah, I see whats happening

Thanks!!