Solving a non-linear system, urgent reply needed!

**mankvill** · July 15th 2008, 07:35 PM

Not sure where to begin on this one. If you tell me how to do this one, it'd help me with the others.

**Isomorphism** · July 15th 2008, 07:52 PM

Originally Posted by mankvill

Not sure where to begin on this one. If you tell me how to do this one, it'd help me with the others.

Substitute for y in the second equation to get a quadratic equation. Now solve this quadratic and try both roots to get values for y.

Try it

**mankvill** · July 15th 2008, 07:57 PM

Oh yeah, I always forget to do that!

Now I'm having trouble with this!

(x-2)(x-2) doesn't work.
(x+2)(x-2) doesn't work...

**mankvill** · July 15th 2008, 07:58 PM

Wait.

Is there no solution?

**Isomorphism** · July 15th 2008, 08:08 PM

Sigh...

x^2+ 4x + 1 = - 3

x^2+ 4x + 4 = 0

(x+2)^2 = 0

x = -2

Substiute this value in y = x^2 + 1 = (-2)^2 + 1 = 4+1 = 5

**mankvill** · July 15th 2008, 08:10 PM

Originally Posted by Isomorphism

Sigh...

x^2+ 4x + 1 = - 3

x^2+ 4x + 4 = 0

(x+2)^2 = 0

x = -2

Substiute this value in y = x^2 + 1 = (-2)^2 + 1 = 4+1 = 5

oh, okay. yeah, i'm not good with that.

So is there 1 answer: -2,5?

**Isomorphism** · July 15th 2008, 08:13 PM

Originally Posted by mankvill

oh, okay. yeah, i'm not good with that.

So is there 1 answer: -2,5?

Yes, after all that working out... you should not be this doubtful

**mankvill** · July 15th 2008, 08:14 PM

I know, I'm just taking a test right now! Gotta be sure.

Thanks!

Thread: Solving a non-linear system, urgent reply needed!