# Elimination method in non-linear equation

• Jun 10th 2009, 06:26 AM
galanm
Elimination method in non-linear equation
x^2 + y^2 = 25 and
x^2 + 7y = 37
• Jun 10th 2009, 06:28 AM
Amer
Quote:

Originally Posted by galanm
x^2 + y^2 = 25 and
x^2 + 7y = 37

multiply one of the equation with -1 and add it to the other one
• Jun 10th 2009, 06:29 AM
mr fantastic
Quote:

Originally Posted by galanm
x^2 + y^2 = 25 and
x^2 + 7y = 37

Substitute x^2 = 37 - 7y from the second equation into the first equation and solve the quadratic equation for y.
• Jun 10th 2009, 06:31 AM
galanm
The instructions state to use the elimintation method.
• Jun 10th 2009, 06:36 AM
Amer
Quote:

Originally Posted by galanm
The instructions state to use the elimintation method.

multiply the second one with -1 you will have

\$\displaystyle -x^2-7y=-37\$

find the sum of that and this

\$\displaystyle x^2+y^2=25\$

\$\displaystyle -x^2-7y+x^2+y^2=27-37\$

\$\displaystyle y^2-7y+10=0\$

\$\displaystyle (y-2)(y-5)=0\$

\$\displaystyle y-2=0...y=2 , y-5=0...y=5\$

sub these values of y in one of the equation \$\displaystyle x^2+7y=37\$ or \$\displaystyle x^2+y^2=25\$ you will have the values of x this is elimination you eliminate x ...