Question

Упростите выражение 8z-k / 7z-3k + 4z / 7z-5k

Answer 1

$\frac{8z - k}{7z - 3k} + \frac{4z}{7z - 5k} = \frac{(8z - k)(7z - 5k) + 4z(7z - 3k)}{(7z - 3k)(7z - 5k)} = \\ \frac{56 {z}^{2} - 40kz - 7kz + 5 {k}^{2} + 28 {z}^{2} - 12kz}{(7z - 3k)(7z - 5k)} = \\ \frac{84 {z}^{2} - 59kz + 5 {k}^{2} }{(7z - 3k)(7z - 5k)}$