Then correct your own mistake. "Find the value of x," would patch that hole, I would think. The Fates are kind.
Getting the suspicion I'm just sensitive to funny math, but that's to howl so funny. I fear math teachers are a bit too sour to grade this positive but I wouldn't...
Next time, of course, you write "solve for x". Those whom the Gods wish to destroy They first make mad. -- Euripides