[r]
(1)vA DAo T~O PHU YEN
-KY THI CHQN HQC SINH GIOI LOP THCS NAM HQC
#? ,
MOll thi TOAN ~ BANG A - VONG
Thdi gian laID bai : 150 phut ( Khong kethbi gian giao de )
Bai : ( Rut b) Phan
)
b.1'eA'uth'~c 2~ 3+ ~ - ~13 +.J48
u A=· J6-J2
da thuc sau day tll' :
= +y+z)][(x+ y)(x+ z)] +y2z2
Bai : (
MQt
b) Cho
)
chinh phu'dng s6 a =: 11 11 minh ding
d';lng: , Bi€t =1 Hay tlm
-( 2n chil' ) , b = (n chil' )
lia phu'dng
?
3: ( 5 Giiii
)
phu'dng trlnh :
{X2 +
y2 +
Z2 +
+xy=
+ =19
+zx =28
t\f (p )
nam tren hai
ky tren , Bu'ong
Ifin lu'Q'tt~i
di€m
Bai : ( )
Cho ba diSm dinh A, B, th~ng hang theo
2' r2) cac mla du'ong tron du'ong kinh AB va
m~t ph~ng bo AB GQi H Ia mQt diSm
th~ng vuong g6c vdi AB H dlt nll'a du'ong tron
va E, Hai du'ong th~ng DB va EC dlt t';li M
a Chung minh r~ng tl s6 - kh6ng ph\l thuQc vao vi tri cua
tren
(2)GIAo DlI)CVA DAO T~O PHU YEN
-THI CHQN HQC SINH GIGI LOP THCS NAM HQC
ft? "
Mon thi : TOAN ~ BANG A - VONG Thdi gian lam b~li : 150 phut
( Khong k~ thdi gian giao d~ )
Bai : ( )
a x +y:;:: Chung minh rang vdi X:;i:O va y :;i: ta
x y 2(y - x)
-= -/-1 -1 +3
b TIm nghi~m nguyen eua phudng trlnh :
3(x2 +xy+ y2)=x+8y
BaE : (
Cho
TIm
)
1
dUdng x, y, z thoa man h~ thue - + - = ,
x z y
,,? x+y
tri nha nhftt cua bieu thue f(x,y,z)
::::: -y
Bai : ( )
Chung minh ding vdi x, y , z la dQ dai eua mQt
~ +y- +z-x)(z+x-y)
ta
BilE : ( )
Cho nhQn xOy dinh Di€m A hill dQng
a b
tren eho - + - = k , a, b la cae
dudng eho trude,
Chung di.ng du(jng th~ng AB luon di qua mQt
b) TIm vi eua A, B d€ eho tam giae ABC co chu
va hill eho trude, k