3xy = 1
6x + y = 3
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y = 3 - 6x
3x( 3 - 6x ) = 1
9x - 18x² = 1
18x² - 9x + 1 = 0
D = 81 - 72 = 9 = 3²
x1 = ( 9 + 3 ) : 36 = 12/36 = 1/3
x2 = ( 9 - 3 ) : 36 = 6/36 = 1/6
y1 = 3 - 6*( 1/3 ) = 3 - 2 = 1
y2 = 3 - 6*( 1/6 ) = 3 - 1 = 2
Ответ ( 1/3 ; 1 ) ; ( 1/6 ; 2 )