simultaneous

Happening, existing, or done at the same time. synonym: contemporary.

Containing variables for which there are values that can satisfy all the equations.

Existing, occurring, or operating at the same time; contemporaneous; also, in Aristotelian metaphysics, having the same rank in the order of nature: said of two or more objects, events, ideas, conditions, acts, etc.

Existing, happening, or done, at the same time.

two or more equations in which the values of the unknown quantities entering them are the same at the same time in both or in all.

Occurring or transpiring at the same time.

occurring or operating at the same time