! '( ) "##$ "##%& *+ ),-./ ) 01 '& ! " # $ ≥ % t = −3 + 13 ! & x=± ⇔ ! ' t = −3 − 13 ( L) ! ' t = −3 + 13 ( N ) ! ' 13 − 3& ! " # $ ≥ * + &, '( )4 * ∆' > /* -" ( " ( /* - " ) ⇔ S > ! #* &* 23* P>0 * - # " ) !' # * !' &, 6$ x1,2 = ± t1 , x3,4 = ± t2 x + x + x + x = 2(t + t ) = 2(t1 + t2 )2 − 4t1t2 = 8(m − 1)2 − 4(m − 2) = 8m − 20m + 16 4 4 2 x + x + x + x = 28 ⇔ 8m − 20m + 16 = 28 ⇔ 2m − 5m − = ⇔ 4 * 76 2- 4 '& ⇔ ⇔ x + + x = x( x + 3) ⇔ x + x = x + 5x + ≥ m=− ( L) !' ⇔ ⇔ x =1 x − 18 x + = * 76 2-9 !' - * -6$ ( 3& !' !' x > ∨ x < −1 2x , t > :7 x +1 #/7 & 2x % ( =1⇔ x =1 x +1 * 76 2-: ! ' !' 16( x + x) = 25 x + 30 x + x≥− '( )" (N ) !' x≥0 m=3 !' # $ t − 2t + ≤ t= (" # ! ' !' !' - * -6$ ( !' '& ; $ < * < < * 72 #" ( ! " (> ( !' = 8= = " )! $* =x ≥ 0, y ≥ & '( )5 % 8 = 8= =≥ " ) ? * = * 76 2-@* * -6$ "> ! " (> ( !' !' 3& ⇔ [ xy − − ( x − y ) ] = ⇔ [ ( x + 1)( y − 1) ] = ⇔ # & ( x + 1)( y − 1) = ( x + 1)( y − 1) = −2 !' * -" (> ! " A8> ! "> 8! " A > A( ! " (> ! " A > 8! " A8> ! "> A( '& % = * a < a + a + < (a + 1) B & a2 + a +1 #6$ C7 = * !' a < a2 + a + < a + a2 + a + #6$ C7 D !' 3& EF /7&G H2 = '( )6 a 1+ b 1+ c + + ≥ a ; (1 + b)(1 + c) 8 b 1+ c 1+ a c3 1+ a 1+ b + + ≥ b