: (BT, BX ) (CY, CX) (mod zr)
C{c nam DuCIr1g lich (Quf Ty) c6 ir nh&r
hai chfr sd bidu thi b&i c6ng th*c 60&+33=
l0(6,t+3)+3 v6i t- lir sd tu nhiCn. Tldd suy ra nhfrng n5.m Duong lich (c6 it nhdt hai chtr s0)
th6a min ba didu ki€n sau thi tumg frng vdi
nlm Quf Ty:
r chfr sS hlng don vi lh 3,
r chft sd hhng chuc lDr sd 16 (do 6fr +3 lh sd l6i.
o tdng cdc cht sd chia hdt cho 3.
ChAng hqn c6c nim sau li nini Quf T11: 33,
453, 813, 1533, tgg3, 1953, 2013..".
HoANG NGUYEN
B;ii t. {;,t*} {dH.[t' x,as,t r'ftI$rus* tBi
Dat MN = a * ?0 cm, MQ= b = 19,? cm, Mf
= u, MF= r,, flF =.r., FC = -y' Dd phong bi khdng bi h6'vi c6 diOn tfch bd m[t ldn nh{t thi c6c tam giric dinh gapMffl Nf#. PGI-I, QHf phii phti kfn h)nh chfr nhat fFCll vil khi gdp phei khOng chbm l&n nhau, trlc II c6 Ai{6'F = A(EF"
= APGFI = AIGH vi AQEff = Afffff = AICF
= ATEG.
Suy ra cdc didm H,K,T"F thing hing. Hon nfa"
EM = EK = EQ,GN = GT =GPn€n ru = EM = GN = S? = 9,6 cm"
Vi gG = MN=n ndn x2*-y,::;l2 tl)
Trtng tam gi6c vudng M€F c6 a2 +t'? =,r: {2)
{.".
Trong tam gii{c vuCIng NFG cd
u?+ (a - 4t :-I" (3)
Tt {l), (2}, (3) suy re v?* av + a2= 0. Tiltl6 tinh dtry r,, = 1?,8 cm vh r!= 7,2cm. Do d6 tl6 tinh dtry r,, = 1?,8 cm vh r!= 7,2cm. Do d6
PHI PHI
Bit, 3. {-,,6px *E{F,q },frflruffi s&rufi$ nh'&E,q.'fi'
xa,,&q: gxd!
Ta c6 l=20:9=2j+30;5=2:+20;9=21+2().
Ban Thang lu6n thing ndu s& dung thuAt c[rn
hoa nhu sau:
Ldn ddu banThring cam 4 b0ng m&u tirn. Cdn lai I b6ng miu d6, 9 bOng mlu virng, 1 b0ng
rn[u tim v] 9 bdng miu hdng.
Cric liln sau, ndu b4n L{.rt cdrn I bdng miu dd {hof,c tirn) thi ban Thring s€ ci{m I b0ng m}u tim {ho5c d6}; ndu ban ltrr cim rr(l<niS9} bdng mlu ving (hc6c hdng) thi ban llreirig sE
c*m rr bdng mlu hdng {ho[c v]ng).
THANH LOAN
T4p chf TII&T-I H5,0n duong cdc ban sau cd
l$i gi*i t$r:
l\ Phan Xudn *{tr,l 1C4. THFrf Nam D}ur 2,
Narn Dhn. Nghe An.
2) Tr"dx lfg+dzr ?i'y, 1lC3A, THPT chuy0n
Hr)ng Vuong, TPPleiku, Gia Lai.
3t D6 f{ga.vdir ff*ringArr}, 12Toiin 1, THIrI
chuy€n Le Quf D0n, Bi Ria-Y&ng Thu. f,G= 16cil1. .r1 t _-_x,,*: i t ./ ti ', i ll' i ..:" r."l-. 'i. j .lr'.. I '--.- \i : i;".__ ,.,J ""-_{,, : .- . - ,t-i . -- -l , t) !,, i, egsu q:,:r,)--l?ff-.HB5 *,