Bridging to MatrixMath's LU-based solver for a linear system. A genuinely nonlinear system falls back to Symbolic.solveSystemNumeric (damped Newton's method) automatically, finding one root near its default initial guess -- a system with multiple solutions may not find every one, and a singular system still throws rather than returning a wrong answer. Add or remove equations freely -- just keep the equation count matching the variable count (a square system).