2 và 3/5ha = m2
mời các cao nhân
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\hept{\begin{cases}\frac{x}{2}=\frac{y}{3}\Leftrightarrow\frac{x}{10}=\frac{y}{15}\\\frac{z}{4}=\frac{y}{5}\Leftrightarrow\frac{z}{12}=\frac{y}{15}\end{cases}\Leftrightarrow\frac{x}{10}=\frac{y}{15}=\frac{z}{12};x+y-z=-39}\)
Tính chất dãy tỉ số bằng nhau:
\(\frac{x}{10}=\frac{y}{15}=\frac{z}{12}=\frac{x+y-z}{10+15-12}=-\frac{39}{13}=-3\)
\(\Rightarrow\hept{\begin{cases}\frac{x}{10}=-3\Leftrightarrow x=-30\\\frac{y}{15}=-3\Leftrightarrow y=-45\\\frac{z}{12}=-3\Leftrightarrow z=-36\end{cases}}\)
\(=4\left(2,86+3,14\right)-6,01.5+3\)
\(=4.6-30,05+3\)
\(=27-30,05=-3,05\)
1 We should recycle plastic bags and jars
2 How can I get to the nearest bus stop?
3 We are going rafting so you should bring a towel
4 Because of feeling tired, I went to bed early
5 It is not difficult to recycle paper
`(x^2 - 5x + 7)^2 - (2x - 5)^2 = 0`
`<=> x^4 + 25^2 + 49 - 10x^3 - 70x + 14x^2 - (4x^2 - 20x + 25) = 0`
`<=> x^4 - 10x^3 + 39x^2 - 70x + 49 - 4x^2 + 20x - 25 = 0`
`<=> x^4 - 10x^3 + 35x^2 - 50x + 24 = 0`
`<=> x^4 - 4x^3 - 6x^3 + 24x^2 + 11x^2 - 44x - 6x + 24 = 0`
`<=> (x - 4)(x^3 - 6x^2 + 11x - 6) = 0`
`<=> (x - 4)(x^3 - 3x^2 - 3x^2 + 9x + 2x - 6) = 0`
`<=> (x - 4)(x - 3)(x^2 - 3x + 2) = 0`
`<=> (x - 4)(x - 3)(x - 2)(x - 1) = 0`
`<=> x ∈ {4,3,2,1}`
Vậy `S = {4; 3; 2; 1}`
\(\left(x^2-5x+7\right)^2-\left(2x-5\right)^2=0\)
\(\Leftrightarrow\left(x^2-5x+7\right)^2=\left(2x-5\right)^2\)
\(\Leftrightarrow\left|x^2-5x+7\right|=\left|2x-5\right|\)
\(\Leftrightarrow\left[{}\begin{matrix}x^2-5x+7=-2x+5\\x^2-5x+7=2x-5\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x^2-3x+2=0\\x^2-7x+12=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\left[{}\begin{matrix}x=2\\x=1\end{matrix}\right.\\\left[{}\begin{matrix}x=4\\x=3\end{matrix}\right.\end{matrix}\right.\)
`2 3/5 ha = 2,6 ha = 2,6 xx 10000=26000 m^2`
26000 m2