  We present a general method, called Qade, for solving differential equations
using a quantum annealer. The solution is obtained as a linear combination of a
set of basis functions. On current devices, Qade can solve systems of coupled
partial differential equations that depend linearly on the solution and its
derivatives, with non-linear variable coefficients and arbitrary inhomogeneous
terms. We test the method with several examples and find that state-of-the-art
quantum annealers can find the solution accurately for problems requiring a
small enough function basis. We provide a Python package implementing the
method at gitlab.com/jccriado/qade.
