( 3x - y + 2 )/7 + ( x + 4y )/2 = 4
( 3x - y + 2 )/7 - ( x + 4y )/3 = - 1
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3x - y + 2 = a
x + 4y = b
( a / 7 ) + ( b / 2 ) = 4
( a / 7 ) - ( b / 3 ) = - 1
2a + 7b = 56
3a - 7b = - 21
5a = 35
a = 7
( 7 / 7 ) - ( b / 3 ) = - 1
b / 3 = 1 + 1
b = 6
3x - y + 2 = 7
x + 4y = 6
x = 6 - 4y
3( 6 - 4y ) - y + 2 = 7
18 - 12y - y + 2 = 7
- 13y = 7 - 20
y = 1
x = 6 - 4 = 2
( 2 ; 1 )
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Xo( yo + 7 ) = 2( 1 + 7 ) = 2*8 = 16
ОТВЕТ 16