SOLUTION: solve the system by addition and substitution methods 4x-4y=-8 y=2+x

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Question 120508: solve the system by addition and substitution methods
4x-4y=-8
y=2+x
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

Start with the given system
4x-4y=-8
y=2%2Bx



4x-4%282%2Bx%29=-8 Plug in y=2%2Bx into the first equation. In other words, replace each y with 2%2Bx. Notice we've eliminated the y variables. So we now have a simple equation with one unknown.


4x-8-4x=-8 Distribute


-8=-8 Combine like terms on the left side


0=-8%2B8Add 8 to both sides


0=0 Combine like terms on the right side


0=0 Simplify

Since this equation is always true for any x value, this means x can equal any number. So there are an infinite number of solutions.