Giúp mik vs nha
a) |x-3|+|y+4|=1
b) (3x+1)2 +|y-5|=1
c) |x+1|+|x-1|=2
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a: \(\left(x+\dfrac{1}{4}\right)+\left(3x-4\right)+2\left(x-3\right)=1\)
=>\(x+\dfrac{1}{4}+3x-4+2x-6=1\)
=>\(6x-\dfrac{39}{4}=1\)
=>\(6x=1+\dfrac{39}{4}=\dfrac{43}{4}\)
=>\(x=\dfrac{43}{4}:6=\dfrac{43}{24}\)
b: \(2\left(x-3\right)=3\left(x+2\right)-x+1\)
=>\(2x-6=3x+6-x+1\)
=>2x-6=2x+7
=>-6=7(vô lý)
c: \(x\left(x+3\right)+x\left(x-2\right)=2x\left(x-1\right)\)
=>\(x^2+3x+x^2-2x=2x^2-2x\)
=>3x-2x=-2x
=>3x=0
=>x=0
d: \(\left(x-1\right)\cdot3x-2\left(x+2\right)-2x=x\left(x-1\right)\)
=>\(3x^2-3x-2x-4-2x=x^2-x\)
=>\(3x^2-7x-4-x^2+x=0\)
=>\(2x^2-6x-4=0\)
=>\(x^2-3x-2=0\)
=>\(x=\dfrac{3\pm\sqrt{17}}{2}\)
a) |x-3|+|y+4|=1
Xét : \(\hept{\begin{cases}|x-3|\ge0\\|y+4|\ge0\end{cases}}\)
Mà : \(|x-3|+|y+4|=1\)
=) Ix-3I=0 và |y+4|=1 hoặc |y+4|=0 và Ix-3I=1
Nếu : |y+4|=0 và Ix-3I=1
=) |y+4|=0
= ) y + 4 = 0
= ) y = 0 - 4 = -4
=) Ix-3I=1
=) \(\hept{\begin{cases}x-3=-1\\x-3=1\end{cases}}\)=) \(\hept{\begin{cases}x=-1+3=2\\x=1+3=4\end{cases}}\)
Nếu : Ix-3I=0 và |y+4|=1
=) Ix-3I=0
=) x-3=0
=) x = 0 + 3 = 3
=) |y+4|=1
=) \(\hept{\begin{cases}y+4=1\\y+4=-1\end{cases}}\)=)\(\hept{\begin{cases}y=1-4=-3\\y=-1-4=-5\end{cases}}\)
`a,x(x-1)-(x+2)^2=1`
`<=>x^2-x-x^2-4x-4=1`
`<=>-5x=5`
`<=>x=-1`
`b,(x+5)(x-3)-(x-2)^2=-1`
`<=>x^2+2x-15-x^2+4x-4+1=0`
`<=>6x-18=0`
`<=>x-3=0`
`<=>x=3`
`c,x(2x-4)-(x-2)(2x+3)=0`
`<=>2x(x-2)-(x-2)(2x+3)=0`
`<=>(x-2)(2x-2x-3)=0`
`<=>-3(x-2)=0`
`<=>x-2=0`
`<=>x=2`
`d,x(3x+2)+(x+1)^2-(2x-5)(2x+5)=-12`
`<=>3x^2+2x+x^2+2x+1-4x^2+25=-12`
`<=>4x+26=-12`
`<=>4x=-38`
`<=>x=-19/2`
a: \(\left\{{}\begin{matrix}x+4y=-11\\5x-4y=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}6x=-10\\x+4y=-11\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{-5}{3}\\y=\dfrac{-11-x}{4}=\dfrac{-11+\dfrac{5}{3}}{4}=-\dfrac{7}{3}\end{matrix}\right.\)
b: \(\left\{{}\begin{matrix}2x-y=7\\3x+5y=-22\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}6x-3y=21\\6x+15y=-66\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}-18y=78\\2x-y=7\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=\dfrac{-13}{3}\\x=\dfrac{y+7}{2}=\dfrac{4}{3}\end{matrix}\right.\)
a,\(11-2x=x-1\Leftrightarrow-2x-x=-1-11\Leftrightarrow-3x=-12\Leftrightarrow x=-4\)
b,\(\text{5(3x+2)=4x+1}\Leftrightarrow15x+10=4x+1\Leftrightarrow15x-4x=1-10\Leftrightarrow11x=-9\Leftrightarrow x=\dfrac{-9}{11}\)
c,\(x^2-4-\left(x-2\right)\left(x-5\right)\Leftrightarrow\left(x+2\right)\left(x-2\right)-\left(x-2\right)\left(x-5\right)\Leftrightarrow\left(x-2\right)[\left(x+2\right)-\left(x-5\right)]\Leftrightarrow\left(x-2\right)\left[x+2-x+5\right]\Leftrightarrow\left(x-2\right)7\Leftrightarrow7x-14\)
Bài 1:
a: \(\Leftrightarrow x-1\in\left\{1;-1;3;-3\right\}\)
hay \(x\in\left\{2;0;4;-2\right\}\)
A = 2x2 - 6xy - 3xy - 6y - 2x2 + 8xy + 6y
= - xy
= \(\frac{2}{3}\)\(x\)\(\frac{3}{4}\)
= \(\frac{1}{2}\)
mk đang bận mấy câu kia tương tự nha
please
a, | x - 3 | + | y - 4 | = 1
\(\Rightarrow\hept{\begin{cases}Th1:x-3=1\\Th2:y-4=1\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=4\\y=5\end{cases}}\)
Vậy :....................
b) Em tham khảo link này nhé : https://scontent-hkg3-2.xx.fbcdn.net/v/t1.15752-0/p280x280/89950345_622565401625615_6104301606075891712_n.jpg?_nc_cat=107&_nc_sid=b96e70&_nc_ohc=veu-JDWz3XAAX8GvIoD&_nc_ht=scontent-hkg3-2.xx&_nc_tp=6&oh=3ad75649cfa03543129d6985582a8a79&oe=5E97750A