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a) ( x + 1 ) . ( y + 2 ) = - 5 = -1 .5 = 1.-5 = 5.-1=-5.1
x+1 | -1 | 1 | 5 | -5 |
y+2 | 5 | -5 | -1 | 1 |
x | -2 | 0 | 4 | -6 |
y | 3 | -7 | -3 | -1 |
Vậy có 4 cặp (x;y) là: ...
b) ; c) tương tự nhé!
Vậy có 4 cặp số ( x ; y) là: (-2;3) , ( 0;7) , ( 4;-3) , ( -6;-1)
4:
(x+1)(y-2)=5
=>\(\left(x+1;y-2\right)\in\left\{\left(1;5\right);\left(5;1\right);\left(-1;-5\right);\left(-5;-1\right)\right\}\)
=>\(\left(x,y\right)\in\left\{\left(0;7\right);\left(4;3\right);\left(-2;-3\right);\left(-6;1\right)\right\}\)
\(\frac{1}{x}+\frac{y}{3}=\frac{1}{6}\)
=> \(\frac{1}{x}=\frac{1}{6}-\frac{y}{3}\)
=> \(\frac{1}{x}=\frac{1-2y}{6}\)
=> \(x\left(1-2y\right)=6\)
=> \(x;1-2y\inƯ\left(6\right)=\left\{1;2;3;6\right\}\)
Vì \(y\in N\Rightarrow1-2y\in\left\{1;3\right\}\)
\(\Rightarrow x\in\left\{2;6\right\}\)
Lập bảng :
1 - 2y | 1 | 3 |
x | 6 | 2 |
y | 0 | -1 (loại) |
Vậy ...
\(\frac{3}{4}-2.\left|2x-\frac{2}{3}\right|=\frac{1}{2}\)
\(\Rightarrow2.\left|2x-\frac{2}{3}\right|=\frac{3}{4}-\frac{1}{2}\)
\(\Rightarrow2.\left|2x-\frac{2}{3}\right|=\frac{1}{4}\)
\(\Rightarrow\left|2x-\frac{2}{3}\right|=\frac{1}{4}:2\)
\(\Rightarrow\left|2x-\frac{2}{3}\right|=\frac{1}{8}\)
\(\Rightarrow\orbr{\begin{cases}2x-\frac{2}{3}=\frac{1}{8}\\2x-\frac{2}{3}=\frac{-1}{8}\end{cases}\Rightarrow}\orbr{\begin{cases}2x=\frac{1}{8}+\frac{2}{3}\\2x=\frac{-1}{8}+\frac{2}{3}\end{cases}\Rightarrow\orbr{\begin{cases}2x=\frac{19}{24}\\2x=\frac{13}{24}\end{cases}}}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{19}{24}:2\\x=\frac{13}{24}:2\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{19}{48}\\x=\frac{13}{48}\end{cases}}\)
Vậy ...................................
~ Hok tốt ~
a)\(\left(2x-1\right)^5=32\)
\(\Rightarrow\left(2x-1\right)^5=2^5\)
\(\Rightarrow2x-1=2\)
\(\Rightarrow2x=3\Rightarrow x=\frac{3}{2}\)
b)\(\left(2x+1\right)^2=169\)
\(\Rightarrow\left(2x+1\right)^2=13^2=\left(-13\right)^2\)
\(\Rightarrow2x+1=13\) hoặc \(2x+1=-13\)
\(\Rightarrow2x=12\) hoặc \(2x=-14\)
\(\Rightarrow x=6\) hoặc \(x=-7\)
c)\(x^{100}=x\)
\(\Rightarrow x^{100}-x=0\)
\(\Rightarrow x\left(x^{99}-1\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x^{99}-1=0\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x^{99}=1\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x=1\end{array}\right.\)
a, (2x-1)^5=32
(2x-1)^5=2^5
2x-1=2
2x=2+1
2x=3
x=3:2
x=1,5
Vậy x=1,5
b, (2x+1)^2=169
(2x+1)^2=13^2
2x+1=13
2x=13-1
2x=12
x=12:2
x=6
Vậy x=6
c, x^100=x
=>x=0
x=1