# subsitution method

posted by
**mike**
.

Can some one show me how to use the Substitution method to solve the system of these equations.

x + y = -4

x - y = 2

x + y = 10

y = x + 8

on the first set.

Solve for either x or y in either equation, then put that value into the other equation.

Example:

x + y = -4

x - y = 2

solve for x in the first:

x= -y-4

Put it in the second then..

-y-4 -y=2

-2y=6

y=-3

then solve for x..

x=-y-4=-1