# Thread: Solving a nonlinear system

1. ## Solving a nonlinear system

x^2+y^2=25
x+y=5

I can't figure out how to do this problem. It looks fairly simple, but I keep getting answers that don't make sense.

2. ## Re: Solving a nonlinear system

x=5-y so (5-y)^2+y^2=25

3. ## Re: Solving a nonlinear system

That's what i got, but it's a multiple choice question and the options are A. (0,5) and (5,0) B.(5,-5) and (-5,-5) C.(0,-5) and (-5,0) and D.(0,0) and (5,-5)
If you continue 25-y^2+y^2=25
25=25? does that mean x and y are 0?

4. ## Re: Solving a nonlinear system

$\displaystyle (5-y)^2+y^2=25$

$\displaystyle 25-10y+y^2+y^2=25$

$\displaystyle -10y+2y^2=0$

Finish it.

5. ## Re: Solving a nonlinear system

Originally Posted by hubbabubba590
That's what i got, but it's a multiple choice question and the options are A. (0,5) and (5,0) B.(5,-5) and (-5,-5) C.(0,-5) and (-5,0) and D.(0,0) and (5,-5)
If you continue 25-y^2+y^2=25
25=25? does that mean x and y are 0?
If it's a multiple choice question, you could just substitute each of the possibilities into your system and see which one satisfies the equations...