5-3х-9=11-5х
-3х+5х=-5+9+11
2х=15
х=7,5
5Y = 5Y
( 4X + 1)^2 = ( X + 4)^2
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16X^2 + 8X + 1 = X^2 + 8X + 16
16X^2 - X^2 + 8X - 8X = 16 - 1
15X^2 = 15
X^2 = 1
X1 = 1
X2 = - 1
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5Y = X^2 + 8X + 16
5Y = 1 + 8 + 16 = 25
Y1 = 5
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5Y = 1 - 8 + 16 = 9
Y2= 9/5 = 1,8
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Ответ ( 1 ; 5 ) ; ( - 1 ; 1,8 )
У=4х+5 у=21
21=4х +5
4х=21-5
х= 16/4
х=4