The given equations are
y= 1/2x +2
2y= x +4
To solve by substitution, we would substitute y= 1/2x +2
into the second equation. It becomes
2(1/2x + 2) = x +4
We would open the bracket on the left hand side of the equation by multiplying the terms inside the bracket by the term outside. It becomes
x + 4 = x = 4
x - x = 4 - 4
0 = 0
The system of equations have infinitely many solutions because if the equations are plotted on a line, then at any point on the line is a solution to the system