联立方程组

[ noun ]
a set of equations in two or more variables for which there are values that can satisfy all the equations simultaneously
<noun.communication>

Simultaneous \Si`mul*ta"ne*ous\, a. [LL. simultim at the same
time, fr. L. simul. See {Simulate}.]
Existing, happening, or done, at the same time; as,
simultaneous events. -- {Si`mul*ta"ne*ous*ly}, adv. --
{Si`mul*ta"ne*ous*ness}, n.

{Simultaneous equations} (Alg.), 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.