1)
V ( 28 + X ) + X = 2
V ( 28 + X ) = 2 - X
( V ( 28 + X ))^2 = ( 2 - X )^2
28 + X >= 0 ; X > = - 28
28 + X = 4 - 4x + x^2
X^2 - 5x - 24 = 0
D = 25 + 96 = 121 = 11^2
X1 = ( 5 + 11 ) : 2 = 8
X2 = ( 5 - 11 ) : 2 = - 3
Ответ : - 3 ; 8
2)
V ( 28 + 3x ) + X = 4
V ( 28 + 3x ) = 4 - X
( V ( 28 + 3x ))^2 = ( 4 - X )^2
28 + 3x > = 0 ; 3x >= - 28 ; X > = - 9 ( 1/3 )
28 + 3x = 16 - 8x + x^2
X^2 - 11x - 12 = 0
D = 121 + 48 = 169 = 13^2
X1 = ( 11 + 13 ) : 2 = 12
X2 = ( 11 - 13 ) : 2 = - 1
Ответ : - 1 ; 12