How many solutions does this linear system have?

Y = 2x - 5
-8x - 4y = -20

substitute one equation to the other;
-8x - 4y = -20
-8x - 4(2x - 5) = -20
-16x + 20 = -20

solve for x;
-16x + 20 = -20
-16x = -40
x = 5/2  or 2.5

substitute x = 5/2 to find the y;
y = 2x - 5
y = 2(5/2) - 5
y = 0

one solution; (2.5, 0)   is your answer.

hope this helped, God bless!

21/2 or 5/2