SOLUTION: Hi, I am not sure if this is the correct place for this question but here it goes. I am working on an assignment and one question is giving me fits. The question is "Find the exact

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Hi, I am not sure if this is the correct place for this question but here it goes. I am working on an assignment and one question is giving me fits. The question is "Find the exact      Log On


   

Question 731791: Hi, I am not sure if this is the correct place for this question but here it goes. I am working on an assignment and one question is giving me fits. The question is "Find the exact solutions of the system of equations x^2+2y^2=18 and x=2y." It asks for me to show my work.
If x=2y could I put x into the other equation and make it x^2+(x)^2= 18 then simplify to 2x^2=18 divide and get x^2=9 then it would be x=√9??? But I don't think I understand the correct way to work this problem out enough to be confident in my answers. Thanks so much for your time!
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The question is
"Find the exact solutions of the system of equations x^2+2y^2=18
and x=2y."
Replace x with 2y
(2y)^2 + 2y^2 = 18
4y^2 + 2y^2 = 18
6y^2 = 18
divide both sides by 6
y^2 = 3
y = sqrt%283%29
:
Find x
x = 2sqrt%283%29
:
:
Check solution in original equation
%282sqrt%283%29%29%5E2+%2B+2%28sqrt%283%29%29%5E2 =
4(3) + 2(3) = 18