( x / 2 ) - ( y / 3 ) = 1
( x / 5 ) - ( y / 4 ) = - 1
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3x - 2y = 6
4x - 5y = - 20
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2y = 3x - 6
y = 1,5x - 3
4x - 5( 1,5x - 3 ) = - 20
4x - 7,5x + 15 = - 20
- 3,5x = - 35
x = 10
y = 15 - 3 = 12
Ответ ( 10 ; 12 )