( X - 2)*( X + 3 ) = 24
X^2 + 3X - 2X - 6 = 24
X^2 + X - 30 = 0
D = 1 + 120 = 121 ; √ D = 11
X1 = ( - 1 + 11 ) : 2 = 5
X2 = ( - 1 - 11 ) : 2 = - 6
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( 2T - 1)^2 - 4T = 13
4T^2 - 4T + 1 - 4T = 13
4T^2 - 8T - 12 = 0
2 * ( 2T^2 - 4T - 6 ) = 0
D = 16 + 48 = 64 ; √ D = 8
T1 = ( 4 + 8 ) : 4 = 3
T2 = ( 4 - 8 ) : 4 = - 1