X^2 - 5x = 14
x^2 - 5x - 14 = 0
D = 25 + 56 = 81 = 9^2
x1 = ( 5 + 9 ) : 2 = 7
x2 = ( 5 - 9 ) : 2 = - 2
ОТВЕТ 7 ; - 2
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9 + 4x^2 - 12x = 0
4x^2 - 12x + 9 = 0
D = 144 - 144 = 0
x = 12 : 8 = 1,5
ОТВЕТ 1,5
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2x^2 - 9x - 5 = 0
D = 81 + 40 = 121 = 11^2
x1 = ( 9 + 11 ) : 4 = 5
x2 = ( 9 - 11 ) : 4 = - 0,5
ОТВЕТ 5 ; - 0,5
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4x^2 = 9 + 16x
4x^2 - 16x - 9 = 0
D = 256 + 144 = 400 = 20^2
x1 = ( 16 + 20 ) : 8 = 4,5
x2 = ( 16 - 20 ) : 8 = - 0,5
ОТВЕТ 4,5 ; - 0,5
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3 + 4x^2 - x = 0
4x^2 - x + 3 = 0
D = 1 - 48 = - 47
D < 0
ОТВЕТ нет решений
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x^2 + x = 0
x( x + 1 ) = 0
x = 0
x + 1 = 0
x = - 1
ОТВЕТ 0 ; - 1
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8 - 2с^2 = 0
2( 4 - c^2 ) = 0
2( 2 - c )( 2 + c ) = 0
2 - c = 0
c = 2
2 + c = 0
c = - 2
ОТВЕТ 2 ; - 2