giúp mik vs 2x+5=x-1  mik bí lắm r

Bài 1:

ta có:\(\hept{\begin{cases}a.b=18\\a+b=11\end{cases}}\)

pt (1) \(\Leftrightarrow b\left(11-b\right)=18\)

\(\Rightarrow11b-b^2=18\)

\(\Rightarrow-\left(11b+b^2\right)=18\)

\(\Rightarrow b^2+11b=18\)

\(\Rightarrow b^2+11b+18=0\)

\(\Rightarrow b^2+11b+22-4=0\)

\(\Rightarrow\left(b+11\right)-4=0\)

\(\Rightarrow\left(b+11+2\right).\left(b+11-2\right)=0\)

\(\Rightarrow\left(b+13\right).\left(b+9\right)=0\)

\(\Rightarrow\hept{\begin{cases}b=-13\Leftrightarrow a=2\\b=-9\Leftrightarrow a=-2\end{cases}}\)

Bài 2:

2)

P=-[(2x-6)2+/-5-y/-37]

Vi (2x-6)2 ≥0 , /-5-y/≥0 nên (2x-6)2+/-5-y/-37-37/ => P≤37

Dấu = xảu ra khi x=3 , y=-5

Vậy Max P=37 khi x=3 , y=-5

chúc bạn học tốt !

\(\dfrac{3}{5}x-\dfrac{1}{2}x=\dfrac{3}{2}-0\)

\(\left(\dfrac{3}{5}-\dfrac{1}{2}\right)x=\dfrac{3}{2}\)

\(\dfrac{1}{10}\cdot x=\dfrac{3}{2}\)

\(x=\dfrac{3}{2}:\dfrac{1}{10}\)

\(x=15\)

\(\dfrac{3}{5x}-\dfrac{1}{2x}=\dfrac{3}{2-0}\)

\(\dfrac{3}{5x}+\dfrac{-1}{2x}=\dfrac{3}{2}\)

\(\dfrac{3}{5}+\dfrac{-1}{2}=\dfrac{3}{2}\cdot x\)

\(\dfrac{1}{10}=\dfrac{3}{2}\cdot x\)

\(\dfrac{3}{2}\cdot x=\dfrac{1}{10}\)

     \(x=\dfrac{1}{10}\div\dfrac{3}{2}\)

    \(x=\dfrac{2}{30}\)

    \(x=\dfrac{1}{15}\)

Để\(\dfrac{4}{2x+3}\)là số nguyên thì 4⋮2x+3

2x+3∈Ư(4)

Ư(4)={1;-1;2;-2;4;-4}

⇒x∈{-1;-2}

Tổng giá trị nguyên của x là

(-1)+(-2)=(-3)

`-4/5 + 2x =1/3 -2/3x`

`=>  2x + 2/3x =1/3 +4/5`

`=> (2 +2/3) x= 5/15 + 12/15`

`=> ( 6/3 +2/3) x= 17/15`

`=> 8/3 x= 17/15`

`=> x= 17/15 : 8/3`

`=> x= 17/15 xx 3/8`

`=>x=17/40`

` @ ` \(yeuugialinhh\)

Conf yeeu Gia Linh nwax :< 

a, 3 ( x+2 ) + 2 ( x-3 ) =10

      3x + 6 + 2x - 6   = 10

                            5x = 10

                       x        =   10 : 5

                       x = 2

b, 720 : ( 41 - ( 2x-5 )) = 40

     720 : ( 41-2x + 5) = 40

            720 : ( 46 - 2x ) = 40

                        46 - 2x = 720 : 40

                        46 - 2x = 18

                               2x = 46 - 18

                                2x = 28

                                 x= 28 : 2

                                 x = 14

Để \(\dfrac{11}{2x+3}\) nhận giá trị nguyên thì \(2x+3\inƯ\left(11\right)=\left\{\pm1;\pm11\right\}\)
Ta có bảng sau:

Vậy để \(\dfrac{11}{2x+3}\) nhận giá trị nguyên thì \(x\in\left\{-7;-2;-1;4\right\}\)

Để \(\dfrac{11}{2x+3}\)là số nguyên khi:

2x+3ϵƯ(11)= {-1;1;-11;11}

Ta có bảng sau:

⇒x ϵ {-2;-1;-7;4} 

các bạn ơi nhanh lên mình k cho

\(xy+2x-y=4\)

\(\Leftrightarrow x\left(y+2\right)-y-2=2\)

\(\Leftrightarrow x\left(y+2\right)-\left(y+2\right)=2\)

\(\Leftrightarrow\left(x-1\right)\left(y+2\right)=2\)

\(TH1:\hept{\begin{cases}x-1=1\\y+2=2\end{cases}\Rightarrow\hept{\begin{cases}x=2\\y=0\end{cases}}}\)

\(TH2:\hept{\begin{cases}x-1=2\\y+2=1\end{cases}\Rightarrow\hept{\begin{cases}x=3\\y=-1\end{cases}}}\)

\(TH3:\hept{\begin{cases}x-1=-1\\y+2=-2\end{cases}\Rightarrow\hept{\begin{cases}x=0\\y=-4\end{cases}}}\)

\(TH4\hept{\begin{cases}x-1=-2\\y+2=-1\end{cases}\Rightarrow\hept{\begin{cases}x=-1\\y=-3\end{cases}}}\)

Vậy\(\left(x;y\right)\in\left\{\left(2;0\right),\left(3;-1\right),\left(0;-4\right),\left(-1;-3\right)\right\}\)