Answer:
The reason why most of the answers regarding this problem say "all of them have only one solution" is because the x's in the equations are meant to be raised to a power.
Explanation:
So, y=-5^-x and y=x+5 when graphed would have 0 solutions.
y=4(1.2)^x and y=x+7 would have two solutions.
And y=(0.5)^x and y=6 would have one solution.