SOLUTION: need help solving for x and y using substitution i understand the principal but having trouble with this one problem 6x-y=8 -x-y=0

Algebra ->  Linear-equations -> SOLUTION: need help solving for x and y using substitution i understand the principal but having trouble with this one problem 6x-y=8 -x-y=0      Log On


   



Question 718962: need help solving for x and y using substitution
i understand the principal but having trouble with this one problem
6x-y=8
-x-y=0

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
-1 x + -1 y = 0 .............1
-1 y = 0 + 1 x
/ -1 =
y = 0 + -1 x
6 x + -1 y = 8 .....................2
Substitute y in (2)
6 x + -1 ( 0 + -1 x ) = 8
6 x + 0 + 1 x = 8
6 x 1 x = 8
7 x = 8
/ 7
x= 8/ 7
Plug the value of x in (1)
-1 x + -1 y = 0
-1 * 8/ 7 + -1 y = 0
-1 1/ 7 + -1 y = 0
-1 y = 8/ 7
/ -1
y= -8/ 7
m.ananth@hotmail.ca