Which function is strictly decreasing on R\mathbb{R}R?
f(x)=exf(x) = e^xf(x)=ex
f(x)=∣x∣f(x) = |x|f(x)=∣x∣
f(x)=−x+1f(x) = -x + 1f(x)=−x+1
f(x)=x2f(x) = x^2f(x)=x2