How many solutions does this linear have?

y = 2x+4

x + 2y = 8

y = 2x + 4

in standard form is

2x - y = - 4

Second equation is

x + 2y = 8

Those aren't parallel.

Answer: exactly one solution

Let's solve,

x + 2 (2x + 4) = 8

5x + 8 = 8

5x = 0

x = 0

y = 2x + 4 = 4

Solution is (0,4)