2x^2+y^2+2xy-6x-2y+10

=(x+y+1)^2+(x-2)^2+5>=5

Amin=5 khi : x+y+1=0

               hoac  x-2=0

=>x=2 va y=-3

tim m de gtln cua bieu thuc sau=-3:a=-2x^2-y^2-2xy+6x-2y+2m-7

tim cac cap x;y thoa man:

a)x^2 - 2x +y^2 + 1=0

b)-2x^2+4x-y^2-2y-3=0

c)x^2+2y^2-2xy+2x-6y+5=0

bien doi cac bieu thuc lam xuat hien binh phuong:
a=x^2-4xy+2y^2+10
b= - x^2  +3xy + y^2 - 2
c=2x^2+2xy+4x+y^2+1
d=x^2+2x+2y+y^2-7
e=2x^2+2xy+4x+2y+5
f= - x^2+4x-2xy+y^2-7y+16

giai giup minh voi

bien doi cac bieu thuc lam xuat hien binh phuong:
a=x^2-4xy+2y^2+10
b= - x^2  +3xy + y^2 - 2
c=2x^2+2xy+4x+y^2+1
d=x^2+2x+2y+y^2-7
e=2x^2+2xy+4x+2y+5
f= - x^2+4x-2xy+y^2-7y+16

bien doi cac bieu thuc lam xuat hien binh phuong:

A=x^2-4xy+2y^2+10

cho tam giac abc can tai a,ve duong cao bd va ce .tren tia doi cua tia ba lay m,tren tia doi cua tia ca lay n sao cho bm=cn.

a)cm:tam giac ecn=tam giac bdm

b)cm:ed \\ mn

cho tam giac abc vuong tai a,co ab=3cm,ac=4cm.

a)tinh bc va so sanhcac goc cua tam giac abc

b)ke ah vuong goc voi bc,lay d tren bc sao cho h la trung diem cua bd.cm:tam giac abd can tai a

c)tren ah lay m sao cho h la trung diem cua am.cm:tam giac abm la tam giac can