Tìm x,y:
a,/x-1/+/x-3/<x+1.
b,/x+y+2/+/2y+1/<hoặc=0.
c,/x-y-5/+(y-3)^2016=0.
Tìm x,y:
a) \(\left|x-3\right|+\left|y-1\right|=0\)
Giải chi tiết dùm mình nha. Thanks
Có: \(\left\{{}\begin{matrix}\left|x-3\right|\ge0\forall x\\\left|y-1\right|\ge0\forall y\end{matrix}\right.\)
\(\Rightarrow\left|x-3\right|+\left|y-1\right|\ge0\forall x;y\)
Mà: \(\left|x-3\right|+\left|y-1\right|=0\)
nên: \(\left\{{}\begin{matrix}x-3=0\\y-1=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=3\\y=1\end{matrix}\right.\)
1. Tìm x,y:
a) (x+2)2 + (x-3)2 = 2x ( x+ 7)
b) x3- 3x2 + 3x - 126 = 0
c) x2 + y2 - 2x + 4y + 5 = 0
d) 2x2 - 2xy + y2 + 4x + 4 = 0
\(a.\left(x^2+4x+4\right)+\left(x^2-6x+9\right)=2x^2+14x\)
\(x^2+4x+4+x^2-6x+9-2x^2-14x=0\)
\(-18x+13=0\)
\(x=\dfrac{13}{18}\)
Vậy \(S=\left\{\dfrac{13}{18}\right\}\)
\(b.\left(x-1\right)^3-125=0\)
\(\left(x-1\right)^3=125\)
\(x-1=5\)
\(x=6\)
Vậy \(S=\left\{6\right\}\)
\(c.\left(x-1\right)^2+\left(y +2\right)^2=0\)
\(Do\left(x-1\right)^2\ge0\forall x;\left(y+2\right)^2\ge0\forall y\)
\(\Rightarrow\left(x-1\right)^2+\left(y+2\right)^2\ge0\forall x,y\)
Mà \(\left(x-1\right)^2+\left(y+2\right)^2=0\)
\(\Rightarrow\left[{}\begin{matrix}\left(x-1\right)^2=0\\\left(y+2\right)^2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\y+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\y=-2\end{matrix}\right.\)
Vậy \(S=\left\{1;-2\right\}\)
\(d.x^2-4x+4+x^2-2xy+y^2=0\)
\(\left(x-2\right)^2+\left(x-y\right)^2=0\)
\(\Rightarrow\left[{}\begin{matrix}\left(x-2\right)^2=0\\\left(x-y\right)^2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\x-y=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\y=2\end{matrix}\right.\)
Vậy \(S=\left\{2;2\right\}\)
Bài 1: b) 2x+6 chia hết cho x-3
d) x-1 chia hết cho 2x+1
Bài 2:Tìm chữ số x,y:a)x479y chia hết 36
Bài 1:
b) \(2x+6⋮x-3\)
\(\Leftrightarrow2\left(x-3\right)+12⋮x-3\)
Mà \(2\left(x-3\right)⋮x-3\)
\(\Rightarrow12⋮x-3\)
làm nốt
d) \(x-1⋮2x+1\)
\(\Leftrightarrow2x-2⋮2x+1\)
\(\Leftrightarrow2x+1-3⋮2x+1\)
Mà \(2x+1⋮2x+1\)
\(\Rightarrow3⋮2x+1\)
Làm nốt
Bài 2:
\(x479y⋮36\)
\(\Leftrightarrow x479y⋮4;9\)
+) Để \(x479y⋮4\)
\(\Leftrightarrow9y⋮4\)mà y là chữ số nên y<10
\(\Rightarrow y\in\left\{2;6\right\}\)
TH1:\(y=2\)Thay vào ta được :
\(x4792⋮9\)
\(\Leftrightarrow x+4+7+9+2⋮9\)
\(\Leftrightarrow x+22⋮9\)Mà x là chữ số
\(\Rightarrow x=5\)
TH2: \(y=6\)thay vào ta được :
\(x4796⋮9\)
\(\Leftrightarrow x+4+7+9+6⋮9\)
\(\Leftrightarrow x+26⋮9\)Mà x là chữ số
\(\Rightarrow x=1\)
Vậy \(\left(x;y\right)=\left\{\left(5;2\right);\left(1;6\right)\right\}\)
Bài 1: Tìm các số nguyen x,y:a ) xy - 2x - y= -6
Tìm x,y:a, ( x + y )^2020 + I 2021 - y I ≤ 0b, I 3x + 2y I^209 + I 4y - 1 I^2020 ≤ 0
tìm y:
a) (y + 5) x 2020 = (200 + 5) x 2020
b) y - 45600 = (2019 - 419) x 4 x 25
a) (y + 5) x 2020 = 205 x 2020
(y + 5) x 2020 = 414100
y + 5 = 414100 : 2020 = 205
y = 205 - 5 = 200
a) y= 200
b) y-45600 = 1600 × 4 ×25
y-45600=160000
y= 114400
b) y - 45600 = (2019 - 419) x 4 x 25
y - 45600 = 1600 x 100
y - 45600 = 160000
y = 160000 + 45600 = 205 600
Tìm y:
a) y x 2,8 + 5,2 x y = 48
b) y x 12,25 – y + y x 2,75 = 1050
\(a,y\times2,8+5,2\times y=48\\ y\times\left(2,8+5,2\right)=48\\ y\times8=48\\ y=\dfrac{48}{8}=6\\ ---\\ b,y\times12,25-y+y\times2,75=1050\\ y\times\left(12,25-1+2,75\right)=1050\\ y\times14=1050\\ y=\dfrac{1050}{14}=75\)
a: \(y\cdot2,8+y\cdot5,2=48\)
=>\(y\left(2,8+5,2\right)=48\)
=>\(8y=48\)
=>\(y=\dfrac{48}{8}=6\)
b: \(y\cdot12,25-y+y\cdot2,75=1050\)
=>\(y\left(12,25-1+2,75\right)=1050\)
=>\(y\cdot14=1050\)
=>\(y=\dfrac{1050}{14}=75\)
tìm y:
a, y x 27 + y x 30 + y x 44 - y = 10500
b, y x 285 + 115 x y = 400
\(a,y\times27+y\times30+y\times44-y=10500\\\Rightarrow y\times\left(27+30+44-1\right)=10500\\ \Rightarrow y\times100=10500\\ \Rightarrow y=10500:100\\ \Rightarrow y=105\\ b,y\times285+115\times y=400\\ \Rightarrow y\times\left(285+115\right)=40\\ \Rightarrow y\times400=400\\ y=400:400\\ \Rightarrow y=1\)
\(a,\Rightarrow y\times\left(27+30+44-1\right)=10500\\ \Rightarrow y\times100=10500\\ \Rightarrow y=105\\ b,\Rightarrow y\times\left(285+115\right)=400\\ \Rightarrow y\times400=400\\ \Rightarrow y=1\)
Tìm y:
a, y + 847 x 2 = 1953 - 74 b, y : (7 x 18) = 5839 + 8591
Tìm y:
\(a,y+847\times2=1953-74\\ y+847\times2=1879\\ y+1694=1897\\ y=1897-1694\\ y=185\\ b,y:\left(7\times18\right)=5839+8591\\ y:126=14430\\ y=14430\times126\\ y=1818180.\)
a/ y + 847 x 2 = 1953 - 74
y + 1694 = 1879
y = 1879 - 1694
y = 185
b/y : (7 x 18) = 5839 + 8591
y : 126 = 14430
y = 14430 x 126
y = 1818180
#AvoidMe
a. y + 847 x 2 = 1953 - 74
y + 1694 = 1879
y = 1879 - 1694
y = 185
b. y : (7 x 18) = 5839 + 8591
y : 126 = 14430
y = 14430 x 126
y = 1818180
tìm x,y:
a) 2x+1.3y=12x
b) 10x:5y=20y
a: \(\Leftrightarrow\left\{{}\begin{matrix}x+1=2x\\y=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-1\\y=1\end{matrix}\right.\)
2x+1.3y=12x => 2x+1.3y=4x.3x
=> 2x+1.3y=22x.3x => x + 1 = 2x và y = x
=> x = 1 và y = x = 1
Vậy x=y=1