Algebra 1MediumSystems of Equations ShareSystems of Equations · Medium problemSolve the system for xxx and yyy.{−4x+5y=21−4x−y=15\begin{cases} - 4 x + 5 y = 21 \\ - 4 x - y = 15 \end{cases}{−4x+5y=21−4x−y=15 Show answer Walk through it step by step Practice more like this Review this concept