what is the range and why?

Question

y=-e^(x)+15

Answer 1

for e^x the range is any positive real number

y>0

for -e^x the range is any negative real number

y<0

for -e^x +15 the range is any real number less than 15

y<15

y=15 is a horizontal asymptote, f(x) approaches 15 as an upper limit, but never reaches it.