## College Algebra (10th Edition)

$y=Ce^{-2x}$
Subtract $\ln{C}$ on both sides: $\ln{y} - \ln{C}=-2x$ RECALL: For positive real numbers M and N: $\ln{M} - \ln{N} = \ln{\left(\dfrac{M}{N}\right)}$ Use the rule above to obtain: $\ln{\left(\dfrac{y}{C}\right)}=-2x$ RECALL: $\ln{M}= y \longrightarrow e^y=M$ Use the rule above to obtain: $e^{-2x}=\dfrac{y}{C}$ Multiply by $C$ on both sides of the equation to obtain: $C \cdot e^{-2x} = C \cdot \dfrac{y}{C} \\Ce^{-2x} = y \\y=Ce^{-2x}$