Question

Алгебра 8 кл Решите систему уравнений 21

Answer 1

{1/x+y + 1/x-y = 9

{3/x+y + 1/x-y = 11

1/x+y = a, 1/x-y = b

{a+b = 9

{3a+b = 11

(2)-(1):

2a = 2

a = 1

b = 9-a = 8

{1/x+y = 1

{1/x-y = 8

{x+y = 1

{x-y = 1/8

2x = 9/8

x = 9/16

y = 1-x = 7/16