Explicación paso a paso:
(2n+1)x² + 5nx + 20 = 0
2n+1 x² + 5nx + 20 = 0
2nx² + 5nx = 0 -20 -1
7nx² = 19
nx² = 19/7
(5m - 25)x² + (m - 4) x + 4 = 0
5m -25 x² + m - 4 x + 4 = 0
6m + 2x² = 0 + 25 +4 -4
6m + 2x² = 25
