You can use a calculator to create a table of values to check if this statement is true or false. Because $\displaystyle{y}={{e}}^{{x}}\usepackage{cmbright}\Huge\$ , as x decreases, the output y will decrease. This is the same as saying that as x decreases, $\displaystyle{f{{\left({x}\right)}}}\usepackage{cmbright}\Huge\$ will decrease. In other words, as the input decreases, the graph goes down.