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x2 + xy + x + y = 2
x . x + x . y + x + y = 2
x . ( x + y ) + x + y = 2
x . ( x + y ) + ( x + y ) . 1 = 2
( x + y ) . ( x + 1 ) = 2
=> x + 1 thuoc U(2)
=> x + 1 thuoc { 1 ; 2 }
Lap bang :
| x + 1 | 1 | 2 |
| x + y | 2 | 1 |
| x | 0 | 1 |
| y | 2 | 1 |
Vay ( x ; y ) la : ( 0 ; 2 ) ; ( 1 ; 1 )
P/s tham khao nha
\(xy+14+2y+7x=-10\)
\(\Rightarrow xy+7x+7y=-24\)
\(\Rightarrow x\left(y+7\right)+7y=-24\)
\(\Rightarrow x\left(y+7\right)+7y+49=-24+49\)
\(\Rightarrow x\left(y+7\right)+7\left(y+7\right)=25\)
\(\Rightarrow\left(x+7\right)\left(y+7\right)=25\)
\(\Rightarrow\left(x+7\right);\left(y+7\right)\inƯ\left(25\right)=\left\{\pm1;\pm5;\pm25\right\}\)
Xét bảng
| x+7 | 1 | -1 | 5 | -5 | 25 | -25 |
| y+7 | 25 | -25 | 5 | -5 | 1 | -1 |
| x | 6 | -8 | -2 | -12 | 18 | -32 |
| y | 18 | -32 | -2 | -12 | 6 | -8 |
Vậy.........................
\(xy+x+y=2\)
\(\Rightarrow x\left(y+1\right)+\left(y+1\right)=2+1\)
\(\Rightarrow\left(x+1\right)\left(y+1\right)=3\)
\(\Rightarrow\left(x+1\right);\left(y+1\right)\inƯ\left(3\right)=\left\{\pm1;\pm3\right\}\)
Xét bảng
| x+1 | 1 | -1 | 3 | -3 |
| y+1 | 3 | -3 | 1 | -1 |
| x | 0 | -2 | 2 | -4 |
| y | 2 | -4 | 0 | -2 |
Vậy.....................................
\(xy-10+5x-3y=2\)
\(\Rightarrow xy-5x-3y=12\)
\(\Rightarrow x\left(y-5\right)-3y+15=12+15\)
\(\Rightarrow x\left(y-5\right)-3\left(y-5\right)=27\)
\(\Rightarrow\left(x-3\right)\left(y-5\right)=27\)
\(\Rightarrow\left(x-3\right);\left(y-5\right)\inƯ\left(27\right)=\left\{\pm1;\pm3;\pm9;\pm27\right\}\)
Tự xét bảng như trên
\(xy-1=3x+5y+4\)
\(\Rightarrow xy-3x-5y=4+1\)
\(\Rightarrow x\left(y-3\right)-5y+15=1+4+15\)
\(\Rightarrow x\left(y-3\right)-5\left(y-3\right)=20\)
\(\Rightarrow\left(x-5\right)\left(y-3\right)=20\)
\(\Rightarrow\left(x-5\right)\left(y-3\right)\inƯ\left(20\right)=\left\{\pm1;\pm2;\pm4;\pm5;\pm10;\pm20\right\}\)
Xét bảng
| x-5 | 1 | -1 | 2 | -2 | 4 | -4 | 5 | -5 | 10 | -10 | 20 | -20 |
| y-3 | 20 | -20 | 10 | -10 | 5 | -5 | 4 | -4 | 2 | -2 | 1 | -1 |
| x | 6 | 4 | 7 | 3 | 9 | 1 | 10 | 0 | 15 | -5 | 25 | -15 |
| y | 23. | -17 | 13 | -7 | 8 | -2 | 7 | -1 | 5 | 1 | 4 | 2 |
Vậy......................................
\(B=2+2^2+2^3+2^4+...+2^{99}+2^{100}=2\left(1+2^2+2^3+2^4\right)+...+2^{96}\left(1+2^2+2^3+2^4\right)=2.31+2^6.31+...+2^{96}.31=31\left(2+2^6+...+2^{96}\right)⋮31\)
xy+4x+2y=-5
x(4+y)+2(y+4)=3
(4+y)(x+2)=3
=>4+y;x+2 thuộc Ư(3)={-1;1;3;-3}
còn lại lập bản rồi thử từng TH nhé
k đi
Ta có \(|x-y+3|\ge0\forall x,y\)
\(2015\left(2y-3\right)^{2016}\ge0\forall y\)
\(\Rightarrow\hept{\begin{cases}|x-y+3|\ge0\\2015.\left(2y-3\right)^{2016}\ge0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x-y+3=0\\\left(2y-3\right)^{2016}=0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x-y+3=0\\2y-3=0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x-y+3=0\\2y=3\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x-y+3=0\\y=\frac{3}{2}\end{cases}}\)
Bạn thay vào tìm x
Mik cũng hok Toán 2
bài 1: x.(x+7) = 0
Th1:x=0 Th2:x+7=0
=>x=-7
bài 2 (x+12).(x-3)= 0
Th1:x+12=0 Th2:x-3=0
=>x=-12 =>x=3
bài 3 (-x+5).(3-x)=0
Th1 (-x)+5=0 Th2:3-x=0
=>-x=-5 =>x=3
bài 4 x.(2+x).(7-x)=0
Th1:x=0 Th3:7-x=0
Th2:2+x=0 =>x=7
=>x=-2
bài 5 (x-1).(x+2).(-x-3)=0
Th1:x-1=0 Th2:x+2=0
=>x=1 =>x=-2
Th3:-x-3=0
=>-x=-3
\(7x-3xy+3y=19\)
\(\Rightarrow\left(7x-7\right)-\left(3xy-3y\right)=19-7\)
\(7\left(x-1\right)-3y\left(x-1\right)=12\)
\(\left(7-3y\right)\left(x-1\right)=12\)
\(\Rightarrow7-3y;x-1\in\text{Ư}\left(12\right)=\left\{\pm1;\pm2;\pm3;\pm4;\pm6;\pm12\right\}\)
Bạn tự lập bảng rồi làm nốt nhé !
x.(y+3)-y=-2
\(\Rightarrow\)x.( y + 3 ) = y - 2
\(\Rightarrow\)xy + 3x = y - 2
\(\Rightarrow\) y( x - 1 ) + 3( x - 1 ) + 5 = 0
\(\Rightarrow\)y( x - 1 ) + 3( x - 1 ) = -5
\(\Rightarrow\)( y + 3 )( x - 1 ) = -5
\(\Rightarrow\)( y + 3 )( x - 1 ) \(\in\)Ư(-5) = { \(\pm1;\pm5\)}
Ta có bảng sau :
| y + 3 | - 1 | 5 | 1 | -5 |
| x - 1 | 1 | - 5 | 5 | -1 |
| x | 2 | - 4 | - 2 | - 8 |
| y | - 4 | 2 | 6 | 0 |
XY+14+2y+7x=-10
xy*xy+14+2+7=-10
xy*xy+23=-10
xy2=-10-23
xy2=-33