√ ( 18X^2 - 9 ) = X^2 - 4
( √ 18X^2 - 9 ) = ( X^2 - 4)^2
18X^2 - 9 = X^4 - 8X^2 + 16
X^4 - 8X^2 - 18X^2 + 16 + 9 = 0
X^4 - 26X^2 + 25 = 0
X^2 = A ; A > 0
A^2 - 26A + 25 = 0
D = 676 - 100 = 576 ; √ D = 24
A1 = ( 26 + 24 ) : 2 = 25 ; > 0
A2 = ( 26 - 24 ) : 2 = 1 ; > 0
X^2 = 25
X = 5 ; X = - 5
X^2 = 1
X = 1 ; X = - 1
Ответ 5 ; - 5 ; 1 ; - 1
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А жодного порожня множина
1)50-30=20(разница в стоимости)
2)50-100%
20- x%
50x=20*100
x=40%
на 40%
8x^5+1-x^2-8x^3=8x^5-8x^3-(x^2-1)=8x^3(x^2-1)-(x^2-1)=(8x^3-1)(x^2-1)