copy => can xem loi giai dung voi de chua.

dung de bat tinh "x" lai di tim "y"

489 - 123 = 366

bít roy mak bn còn ? lm j

ủng hộ mình nhe

a)

m=1

(1)<=>x^2+x+1-2=0

∆1=1+4=5

x,1,2=(-1±√5)/2

(2)<=>x^2+(1-2)x+8=0

∆2=1-32 <0 vn

b)

x^2+x+m-2(1)

x^2+(m-2)x+8(2)

∆1;1-4m+8=>m≤9/4

∆2: (m-2)^2-4.8≥0

m€(-vc;(2-4√2))U(2+4√2;vc)

dk m(-vc;2-4√2)

z la No chung

(m-3)z+8-m+2=0

m≠3

z=(m-10)/(m-3)

m-3=n

(1)<=>(n-7)^2/n^2+(n-7)/n+n+5=0

(n-7)^2+n(n-7)+n^3+5n^2

n^3+7n^2-21n+49=0

n~2,8

m~5,8>2-2√2 (loai)

khong m thoa man

qua vo van

4950 

tổng là:(0+100)x100:2=4950

A=(x^2+4x+3)/(2x+6)

A=[(x^2+2.2x+4)-1]/[2.(x+3)]

A=[(x+2)^2-1]/[2(x+3)]

A=[(x+2-1)(x+2+1)]/[2(x+3)]

A=(x+1)(x+3)/[2(x+3)]

x≠-3; A=(x+1)/2

chat lop 8.

x+y=1

(x-y)^2 ≥0

x^2+y^2-2xy ≥0

x^2+y^2≥2xy

x^2+y^2+2xy≥2xy+2xy

(x+y)^2≥4xy

1≥4xy

xy≤1/4

x,y>0=>xy>0

<=>1/xy≥4

(x+y)/xy≥4 ™#{1=x+y}!

1/y+1/x≥4

1/x+1/y≥4

x^2+1≥2x

y^2+3≥2.√3y

z^2+5≥2.√5z

x,y,z>0<=>

VT≥2.2√3.2√5xyz=8√15xyz

khi

x=1

y=√3

z=√5

x^2=t≥0

t^2+√(t+2014)=2014

√(t+2014)=a; a≥√2014

a^2=t+2014(1)

t^2+a=2014(2)

(1)-(2)

(a-t)(a+t)=-(a-t)

th1

a=t; =>t≥√2014

(2)=>t^2+t-2014=0

∆=1+4.2014

t=(√(1+4.2014)-1)/2

x=±√t

th2

a+t=-1

a=-t-1=>0≤t≤√(2014)-1

t^2-t-2015=0

(tu gq tiep)