Question

Using elimination to solve the system 2x + y = 8 and x + y = 4, which of the following could be the first step?

Answer 1

First step would be to subtract the two equations, that will eliminate y and then we can find x easily.
\[2x+y=8\]
\[x+y=4\]
Subtract 2nd from 1st
\[2x+y-(x+y)=8-4\]
We get
\[x=4\]
Now to find y, substitute x in any of the equations
We have
\[x+y=4\]
x=4
so
\[y=0\]

Answer 2

so it would be 2x+y=8------> 2x+y=8
(x+y=4) (-1)--> -x-y=-4

Answer 3

Yeah