Ta có :5/x = 1/8 - y/4 = (1-2y)/8
<=> x = 5.8/(1-2y) ; thấy 1-2y là số lẻ nên ƯCLN(8,1-2y) = 1
do đó x/8 = 5/(1-2y)
Để x, y nguyên khi 1-2y phải là ước của 5
*Xét 1-2y = -1 => y = 1 => x = -40
*Xét 1-2y = 1 => y = 0 => x = 40
*Xét 1-2y = -5 => y = 3 => x = -8
*Xét 1-2y = 5 => y = -2 => x = 8
Vậy có 4 cặp (x,y) nguyên (-40,1) ; (40, 0) ; (-8, -5) ; (8, 5)
Tìm x,y,z khi :
a, \(\frac{x}{2}=\frac{y}{3}\) , \(\frac{y}{4}=\frac{z}{5}\) và x - y- z= 28
b, \(\frac{4-z}{1}=\frac{y+z}{2}=\frac{x+y}{3}=\frac{y+8}{5}\)
c, \(\left(x-\frac{1}{5}\right)^{2004}+\left(y+0.4\right)^{100}+\left(z-3\right)^{678}=0\)
a ) Tính A = \(\left(\frac{1}{2^2}-1\right)\left(\frac{1}{3^2}-1\right)\left(\frac{1}{4^2}-1\right)...\left(\frac{1}{100^2}-1\right)\)
b ) Tìm x và y biết : x , y \(\in\) Z và 2x + 2y = 2x+y
Tìm x, biết
|x2-25|+|x2-100|=75
b,\(\left|\frac{x}{2}-2\right|\in Z;\left|\frac{x}{2}-2\right|< 2\)
c, \(\left|x-\frac{1}{3}\right|+\frac{4}{5}=\left|\left(-3,2\right)+\frac{2}{5}\right|\)
Tìm x, y, z
a) \(\sqrt{16}x+\frac{3}{4}=2\sqrt{\frac{4}{25}}+0,01.\sqrt{100}\)
b) \(\left|x\right|+3^2=2^2+\left(\frac{1}{2}\right)^3\)
c) \(2x\left(x-\frac{2}{3}\right)=0\)
d) \(\frac{37-x}{x+13}=\frac{3}{7}\)
Giúp mk vs đg cần gấp nha cảm ơn mấy bạn nhiều lắm !!!
\(\left(\frac{1}{2}\right)^5.x=\left(\frac{1}{2}\right)^7\)
\(\left(\frac{3}{7}\right)^2.x=\left(\frac{9}{21}\right)^2\)
Bài tìm x biết :
2x=2
3x=34
7x=77
(-3)x=(-3)5
(-5)x=(-5)4
2x=4
2x=8
2x=16
3x+1=32
5x-1=5
6x+4=610
52x-7=511
(-2)4x+2=64
\(\left(\frac{1}{2}\right)^x=\left(\frac{1}{2}\right)^5\)
\(\left(\frac{5}{6}\right)^{2x}=\left(\frac{5}{6}\right)^5\)
\(\left(\frac{3}{4}\right)^{2x-1}=\left(\frac{3}{4}\right)^{5x-4}\)
\(\left(-\frac{1}{10}\right)^x=\frac{1}{100}\)
\(\left(-\frac{3}{2}\right)^x=\frac{9}{4}\)
\(\left(-\frac{3}{5}\right)^{2x}=\frac{9}{25}\)
\(\left(-\frac{2}{3}\right)^x=-\frac{8}{27}\)
Tính
B=\(\frac{1}{2}:\left(-1\frac{1}{2}\right):1\frac{1}{3}:\left(-1\frac{1}{4}\right):........:\left(-1\frac{1}{100}\right)\)
Tìm \(x\in Q\) sao cho:
\(\left|x+\frac{1}{101}\right|+\left|x+\frac{2}{101}\right|+\left|x+\frac{3}{101}\right|+...+\left|x+\frac{100}{101}\right|=101x\)
Tính \(S=1+\frac{1}{2}\cdot\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+...+\frac{1}{100}\left(1+2+3+...+100\right)\)
[\(\frac{1}{100}-1^2\)].[\(\frac{1}{100}-\left(\frac{1}{2}\right)^2\)].[\(\frac{1}{100}-\left(\frac{1}{3}\right)^2\)]...[\(\frac{1}{100}-\left(\frac{1}{20}\right)^2\)
