# Simultaenous Eq. with two unknowns

• Jan 9th 2009, 07:31 AM
cheque
Simultaenous Eq. with two unknowns
(root)x+y=11, x+(root)y=7

Can anyone help me to find the values of X and Y? Thanks.
• Jan 9th 2009, 08:33 AM
ajj86
Possible Solution
Quote:

Originally Posted by cheque
(root)x+y=11, x+(root)y=7

Can anyone help me to find the values of X and Y? Thanks.

Well, I just guessed and checked and found that x = 4 and y = 9.

Equation 1: root(4) + 9 = 2 + 9 = 11 This checks out
Equation 2: 4 + root(9) = 4 + 3 = 7 This also checks out

I'll try to find the actual method for arriving at this conclusion.
• Jan 9th 2009, 08:38 AM
cheque
Quote:

Originally Posted by ajj86
Well, I just guessed and checked and found that x = 4 and y = 9.

Equation 1: root(4) + 9 = 2 + 9 = 11 This checks out
Equation 2: 4 + root(9) = 4 + 3 = 7 This also checks out

I'll try to find the actual method for arriving at this conclusion.

$\displaystyle \sqrt(x) = 11-y$*
$\displaystyle x = 121 - 22y +y^2$
$\displaystyle \sqrt(y) = 7-x$
$\displaystyle y = 49 - 14x +x^2$
$\displaystyle 1444 - 1065 x + 272 x^2 - 28 x^3 + x^4 =0$*