Solve the differential equation. Let C represent an arbitrary constant. (Note: In this case, WebAssign expects your answer to have a negative sign in front of the arbitrary C.)

(dz)/(dt) + e^(t+z) = 0

To solve the given differential equation:

(dz)/(dt) + e^(t+z) = 0

we first need to separate the variables.

Rearranging the equation, we have:

(dz)/(dt) = -e^(t+z)

Now, we can multiply both sides by dt to separate the variables:

dz = -e^(t+z) dt

Next, we integrate both sides:

∫ dz = ∫ -e^(t+z) dt

Integrating the left side with respect to z gives us z as the result.

For the right side, we need to apply a u-substitution to integrate -e^(t+z) dt.

Let u = t + z, then du = dt + dz. Rearranging this equation, we have dt = du - dz.

Substituting this back into the integral, we get:

∫ -e^(t+z) dt = ∫ -e^u (du - dz)

Simplifying the right side gives us:

∫ -e^u (du - dz) = ∫ -e^u du + ∫ e^u dz

Integrating both parts separately gives us:

= -∫ e^u du + ∫ e^u dz

= -e^u + ∫ e^u dz

= -e^(t+z) + ∫ e^u dz

= -e^(t+z) + e^u + C

Finally, substituting back u = t + z and rearranging, we have:

z = -e^(t+z) + e^(t+z) + C

Simplifying further, we get:

z = C

Therefore, the solution to the given differential equation is z = C, where C represents an arbitrary constant.