{5x-y=4 {x+4y=-7 {-2x+y=5 {x-9y=6

Question

{5x-y=4 {x+4y=-7
{-2x+y=5 {x-9y=6

Comments

это две системы?

---

{5x-y=4 {-2x+y=5 {x+4y=-7 {x-9y=6

---

да

Answer 1

1)5х-у=4
+
-2х+у=5
3х=9
х=3
у=11
2)х+4у=-7
  х-9у=6 * -1

13у=-13  х=-3
у= -1