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Solving nonlinear systems.

  • Thread starter oray
  • Start date
  • #1
18
0

Homework Statement



Solve the nonlinear system.

x^2-2y^2=16
x^2+y^2=25

Homework Equations



n/a?

The Attempt at a Solution



ive tried subtracting 1 equation from the other...
(x^2-2y^2+9)=25
-(x^2+y^2)=25
-3y^2+9=25
-3y^2=16
y^2=-16/3
y=root of -16/3...
im not even sure if that part is right, also, i dont know where to go after that.
help?
 

Answers and Replies

  • #2
737
0
You've forgotten to subtract the RHS as well.
 
  • #3
18
0
huh? im confused? what is the RHS? i really am confused on where to start in general.
 
Last edited:
  • #4
1,013
65
huh? im confused? what is the RHS? i really am confused on where to start in general.
When you subtracted one equation from the other, you subtracted the left-hand side (LHS) of your equations, but did not do the same for the right-hand side (RHS), which was 25-25 = 0.
 
  • #5
18
0
okay...
(x^2-2y^2+9)=25
-(x^2+y^2)=25
-3y^2+9=0
-3y^2=-9
y^2=-3
y=null?
 
  • #6
Dick
Science Advisor
Homework Helper
26,258
618
You have -3y^2=(-9). That doesn't give you y^2=(-3), does it? I think I remember once dividing -9 by -3 and I didn't get -3.
 
  • #7
18
0
awesome. figured it out. thanks for all the help people :)
 

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