Solve, using the substitution method.
y – 2x = 8
16 + 4x = 2y
a.
the only solution is (24, 0).
b.
there are an infinite number of solutions.
c.
the only solution is (1, 10).
d.
there is no solution.

Y-2x=8 (label equation 1)
16+4x=2y (label equation 2)

divide equation 2 by 2 to find y 
y=2x+8
sub this in equation 1
(2x+8)-2x=8
2x+8-2x=8
8=8

once you get to this point because 8=8 there are an infinite number of solutions because you can't divide by 0. So the answer is B

21, i'm pretty sure it's right lol