S&
GL&O
DVC
VA
DAO
TqO
KY
THI
HQC
SlNH
GTOT
THANH
PH~
-
LOP
9
HA
NO1
NAM
HQC
2012
-
2013

"* 4N-
1
DC
CH~NH
THOC
1
Man:

-
2ax2
+
5bn
-
6
chia
hit
cho
triciia
P
v6i
a=4+&
vB
b=4-&.
Bai
2
(5
diem).
~6~~-~' ry+5~+5y 6=0
a)
Giai
h$
phumg
trinh:
120~'
-y2
-28~+9=0.
b)
Tim

Bhi
4
(7
diin).
Cho
tam
gihc
AAC
co
ba
g6c
nhgn,
noi
tiip
dubng
trbn
(0)
va
AB
<
AC.
Cac
duhg
cao
AD,
BE,
CF
clia
tarn
giac

diem
A,
M,
F,
H,
E
cung
nim
trh
rn+t
duhg
tron.
b)
Goi
N
Il
trung
didm
cua
BC.
Chirmg,minh
ba
di&m
M,H,N
thkg
Mng.
c)
Chhg
minh
BM.AC

1)
do,
ta
lu6n
c6
the
tim
duuc
mat
diim
M
sao
cho
MX,
+
MA,
+

.
+
hQ,,,
2
20
13.
*
f&~
-
- -
- - -
-