b ) x² - 4x - 2y + xy + 1 = 0

( x² - 4x + 4 ) - y ( 2 - x ) -3 = 0

( x - 2 )² - y ( 2 - x ) = 3

( 2 - x ) ( 2 - x - y ) = 3

đến đây lập bảng tìm ra x,y

a) x² + y² + xy + 3x - 3y + 9 = 0

2x² + 2y² + 2xy + 6x - 6y + 18 = 0

( x² + 2xy + y² ) + ( x² + 6x + 9 ) + ( y² - 6y + 9 ) = 0

( x + y )² + ( x + 3 )² + ( y - 3 )² = 0

\(\Rightarrow\)( x + y )² = ( x + 3 )² = ( y - 3 )² = 0

\(\Rightarrow\)x = -3 ; y = 3

Trả lời:

oxit axit

tk mk nha

love

oxit axit

ĐKXĐ : x \(\ne\)0

\(\frac{x-1}{x^2-x+1}-\frac{x+1}{x^2+x+1}=\frac{10}{x.\left(x^4+x^2+1\right)}\)

\(\frac{\left(x-1\right)\left(x^2+x+1\right)-\left(x+1\right)\left(x^2-x+1\right)}{\left(x^2+1-x\right)\left(x^2+1+x\right)}=\frac{10}{x\left(x^4+x^2+1\right)}\)

\(\frac{\left(x^3-1\right)-\left(x^3+1\right)}{\left(x^2+1\right)^2-x^2}=\frac{10}{x.\left(x^4+x^2+1\right)}\)

\(\frac{-2}{x^4+x^2+1}=\frac{10}{x\left(x^4+x^2+1\right)}\)

\(-2x\left(x^4+x^2+1\right)=10\left(x^4+x^2+1\right)\)

\(\Rightarrow\)x = 10 : ( -2 ) = -5

tôi muốm làm bài dễ

Chuyển các câu sau sang bị động QKĐ:

a,People sold all the kets for the trip to the Temple of Literature

-> All the .kets were sold for the trip to the Temple of Literature.

b,Yesterday the thieves stole everything in the safe

-> Everything was stolen in the safe by the thieves yesterday.

c,We told the police about it

-> It was told to the police by us / The police was told about it by us.

d,The police checked every thing in the house

-> Everything in the house was checked by the police.

a,All the kets for the trip to the Temple of Literature were sold.

b,Everything was stolen by the thieves in the safe.

c,The police was told about it.

d,Everything was cheeked by the police in the house.

\(x^2-4x+6=0\)

\(\Leftrightarrow x^2-4x+4+2=0\)

\(\Leftrightarrow\left(x-2\right)^2+2=0\)

\(\Leftrightarrow\left(x-2\right)^2=-2\)( vô lí )

=> vô nghiệm

Vậy tập nghiệm của pt là \(S=\varnothing\)

Bài làm

       \(x^2-4x+6=0\)

\(\Leftrightarrow x^2-4x+4+2=0\)

\(\Leftrightarrow\left(x-2\right)^2+2=0\)

\(\Leftrightarrow\left(x-2\right)^2=-2\)\(\text{( vô lí )}\)

\(\Rightarrow\)\(\text{Vô nghiệm}\)

\(\text{Vậy tập nghiệm của phương trình là }\)\(S=\varnothing\)

\(\text{# Chúc bạn học tốt #}\)