1)\(\dfrac{2^{18}}{32^3}.\dfrac{27^4}{54^3}\)
4)\((\dfrac{1}{2})^x=\dfrac{1}{32}\)
2)\(\dfrac{40^4}{120^4}.\dfrac{130^3}{390^3}\)
5)\(\dfrac{x+1}{9}=\dfrac{4}{x+1}\)
3)\(2^x=8\)
6)\(\dfrac{2x}{5}=\dfrac{10}{x}\)
7)\(19.5^{2x+7}=475\)
8)\(33^x:11^x=243\)
9)Tìm x, y biết: 5x=4y và y-x=7
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Đọc tiếp
| 1)\(\dfrac{2^{18}}{32^3}.\dfrac{27^4}{54^3}\) | 4)\((\dfrac{1}{2})^x=\dfrac{1}{32}\) |
| 2)\(\dfrac{40^4}{120^4}.\dfrac{130^3}{390^3}\) | 5)\(\dfrac{x+1}{9}=\dfrac{4}{x+1}\) |
| 3)\(2^x=8\) | 6)\(\dfrac{2x}{5}=\dfrac{10}{x}\) |
| 7)\(19.5^{2x+7}=475\) | |
| 8)\(33^x:11^x=243\) | |
| 9)Tìm x, y biết: 5x=4y và y-x=7 |
9) Theo bài, ta có : 5x = 4y
\(\Rightarrow\dfrac{x}{4}=\dfrac{y}{5}\)
Mà y - x = 7
Theo tính chất dãy tỉ số bằng nhau, ta có :
\(\dfrac{x}{4}=\dfrac{y}{5}=\dfrac{y-x}{5-4}=\dfrac{7}{1}=7\)
Do đó : \(\dfrac{x}{4}=7\Rightarrow x=7.4=28\)
\(\dfrac{y}{5}=7\Rightarrow y=7.5=35\)
Vậy x = 28 ; y = 35
4) \(\left(\dfrac{1}{2}\right)^x\) = \(\dfrac{1}{32}\)
\(\left(\dfrac{1}{2}\right)^x\)\(=\left(\dfrac{1}{2}\right)^5\)
\(\Rightarrow x=5\)
Vậy x = 5
Nhớ tick cho mk nha !!!