He becamea good doctor.. 3 He was a good doctor. ( ). The days get shorter.. 4 The days are shorter..

102 51 17 1,,. 41 20 7 Θ 102 102 51 102 17 102 51 102 17 =, =, = > > 41 41 20 40 7 42 20 41 7 2 2 a b c a > 0 b > 0 2c > a + b c > ab, : 2 2 c c ab < a < c + c ab x = c c ab, x = c + c ab, x > x, 2 1 c ± c ab,, x, x 2 x 2cx + ab = 0, ( x a)( x a) 1 2 = x x a( x + x ) + a = ab 2ac + a = a( a + b 2c) < 0 x < a < x 2 1 2 1 2 1 2 2 2 2 2 2 2 1 2 1 c c ab < a < c + c ab

1 5x + x x 5x 1 2 = 0 2 : y = 5x 1, 2 2 2 y xy + x 1 = 0, ( y 1)( y x + 1) = 0. 2 10 y 1 = 0, 5x 1 = 1, x = ±. 5 y x + 1 = 0, 5x 1 = x 1, 2 1 x = 1 2 10, x = ±. 5

4 128 3 (3 +1)(3 2 + 1)( 3 + 1) Λ Λ ( 3 + 1) : 2 = 3 1, 1 = + + + + 2 3 1 3 1 3 2 1 3 4 1 3 128 ( )( )( )( ) Λ Λ ( 1 ) 1 = + + + 2 3 2 1 3 2 1 3 4 1 3 128 ( )( )( ) Λ Λ ( 1 ) 1 = + + 2 3 4 1 3 4 1 3 128 ( )( ) Λ Λ ( 1 ) = Λ Λ 1 = + 2 3 128 1 3 128 ( )( 1) 1 2 3 256 = ( 1 )

Θ 5y 2 25 y 2 5 y 0, ± 1, ± 2. y = 1, (x µ 1) 2 = 20, ; 2 y = ±2,( x µ 2) = 5, ; x = 5 x = 5 y = 0 y = 0

1 5,. 1 x + x + 1 = x + x + 5 ( 10 1)

2b + 3c 1 4 = _. a b c = = b 6 8 a a c = 3 ( 1) 4 c c = 4 = 4 ( 2) a a b (1) (2) = 3 a 2b c b c + 3 = 2 + 3 = 2 ( 3 ) + 3 4 = 6 a a a

x k 1 k x 3 = x 3 + 2,. 1 k 5 k 2 2 x 2 2 2 x k x x + = = 1,. x + x x 1 3 6 x + m 3 m + = 0. x x 1 x( x 1) 8x = m + 3 x = m + 3 8 m + 3 x =, 8 m + 3 m + 3 ( 1) = 0 8 8 m m + 3 + 3 = 0 1 = 0 8 8 m = 3 m = 5

2 4 2 2x ± 4x + 4( x x 3 = 2 3 = x ± x 2 3 = x + x 1 x1 2 = ( 1 ± 2 13) 2 3 = x x. 1 x1 2 = ( 1 ± 13) 2 1 x 1 2 = ( 5 ± 13) 6 1 x 1 2 = ( 5 ± 13) 6 2.

1 1 1 1 a + b + c = + + = 1, : a b c 1. a b c 1 1 1 : a + b + c = + + = 1, a b c a + b + c 1 = 0 ( 1) abc ab ac bc = 0 ( 2) AP BP CP D E F, 2, PD PE PF

S S PBC ABC S S S S PCA ABC PAB ABC PBC PCA PAB ABC ABC PD = < AD S + S + S S S S < < 1 3 1 3 ABC 1 3 < 1,. < 1 a b b c c a 1. + + = 0, a b c. 1 + ab 1 + bc 1 + ca 2 2.

20 5 < n < 21 5 n = 21 18 18 48 48 < x < 5 4 96. < x < 12 48 48 7 < < 11 < + 5 < x x 4 3 12b 12b c = 2b < < 4b h h 1 h 1, > >. 2b 12b 4b

= 100% y x( 1 6. 4%) 100%, x( 1 6. 4%) y x( 1 6. 4%) y x 100% 100% = 8% x( 1 6. 4%) x y y x = 117. 100% = 17% x x

1 16 x 1 = x = 5 2 ( ) 5 x = 1 / 5 = 20% : = 100% 2 5 6 55 ( A) ( B) ( C) ( D) 3 6 5 34

17 1 1, 3 9,, 1 2,

1 4 5, ;, 5 5 4 5 x + 4( 4 )., ( ) ( x + 4) 5 4 5. y 4. y + 4 = ( ) ( x + 4). 5

AF = AC 1 = 1 2 ( 180 3 ), 2 = ACD + 3 = 45 + 3. 1 1 = 2, ( 180 3) = 45 + 3, 2 3 = 30 DF AC 3 = 4. 1 1 A AH DF H, AH = DO = AC = AF, 2 2 4 = 30, 3 = 30, 1 = 75 = 2, GC = FC. :S ABC + 2S CDE = 3 8 1 3 AH = CH = 2 2 1 3 S CHA = AH CH =. 2 8

AD BF CE : = 1 DB FC EA : C CG AB l G. BF BE CE CG =, = FC CG EA AD AD BF CE AD BD CG = = 1 DB FC EA DB CG AD BE CF : + = 1 AE AF BE BM CF CN = = AE AG AF AG BCNM DG = ( BM + CN) / 2 BE CF BM CN 2DG + = + = = 1 AE AF AG AG AG

PE PF PD : + = 1 BE CF AD : PG BC G, AH BC H. PD AD PG BC / = AH BC / PE BE = PG AH 2 2 S = S ABC PBC ABC S PAC PF S = = S CF S PE PF PD + BE CF AD S + S + S = S PAC PAB PBC ABC PAB ABC S ABC = = 1 S ABC : AB CB = 1 BE BF OC : OA OC + = 1 OB

2 ( 1) S = S S 0 1 2 ( 2) S = ( S + S ) 1 2 2 S2 BO S0 2 = = S0 = S1 S2 S DO S 0 1 S = S + S + 2S = ( S ) + ( S ) + 2 S S = ( S + S ) 1 2 0 1 2 2 2 1 2 1 2 2 1 1 1 : + + S S S ABC ABD ABE : S = S S = S = S 1 AED 2 BCE ABE S = S + S S = S + S ABC 1 1 + S S ABC 0 2 ABD 0 1 ABD 1 1 = + S + S S + S 0 2 0 1 2S0 + S1 + S2 = 0 S + S (S + S ) + S S = S 2 1 ABE 0 1 2 1 2 S0 + S1 + S0 + S2 = (S + S )(S + S ) 0 2 0 1 2S 0 + S1 + S2 1 = 2 = 2S + S (S + S ) S 0 0 1 2 0

S AED = S BEC = mn 3n = S = n + mn m = 4n CDB ( 1) S = S + S = m + mn = 4n + 4n ABD ABE AED = 6n = 6S CDE S S = 1 6 CDE, ABD 2 S = ( S + S ) = ( 1 + x) ABDE BDO AEO ( 1 + x ) = 3 x 2 2 2 5 1 x = ( ) 2 3 S ABDE = x = + 5 5 SABCDE = + 5 3 2 2

AB = 4 5, AE BF.

x + y. y = x 1 1 x, 2 x 1 1 x y =, x 1, y 2 2 2 2 a b c (2) a b c,

c a + b. c a + b c a + b c a + b c a + b + 2 ab c ( a b) 2 ab?? 2

4 4 4 4 4 4 x, 1000 x 10000, 6 x 9, x 6

γ

2H 2 +O 2 CuO+H 2 2H 2 O Cu+H 2 O C+O 2 CO 2 2C+O 2 2CuO+C CO 2 +C 2CO 2Cu+CO 2 2CO 2CO+O 2 2CO 2 CuO+CO Cu+CO 2 Fe 2 O 3 +3CO 2Fe+3CO 2

= 100% 100 +

CaCO 3 CO 2 +Ca(OH) 2 =CaCO 3 +H 2 O 3 ) 2 CaCO 3 +H 2 O+CO 2 CO 2 CaCO 3 CaCO 3 +CO 2 +H 2 O=Ca(HCO 3 ) 2 CO 2 CO 2 Ca(HCO 3 ) 2 Ca(HCO 3 ) 2 Ca(HCO CaCO 3 CaCO 3 HCl CaCO 3 +2HCl=CaCl 2 +H 2 O+CO 2 CO 2