![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(2x=5y\Rightarrow\dfrac{x}{5}=\dfrac{y}{2}\)
Đặt \(\dfrac{x}{5}=\dfrac{y}{2}=k\Rightarrow x=5k;y=2k\)
\(x^2+2y^2=66\\ \Rightarrow25k^2+8k^2=66\\ \Rightarrow33k^2=66\\ \Rightarrow k^2=2\Rightarrow\left[{}\begin{matrix}k=\sqrt{2}\\k=-\sqrt{2}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=5\sqrt{2};y=2\sqrt{2}\\x=-5\sqrt{2};y=-2\sqrt{2}\end{matrix}\right.\)
Đặt \(\dfrac{x}{5}=\dfrac{y}{2}=k\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=5k\\y=2k\end{matrix}\right.\)
Ta có: \(x^2+2y^2=66\)
\(\Leftrightarrow33k^2=66\)
\(\Leftrightarrow k^2=2\)
Trường hợp 1: \(k=\sqrt{2}\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=5\sqrt{2}\\y=2\sqrt{2}\end{matrix}\right.\)
Trường hợp 2: \(k=-\sqrt{2}\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=-5\sqrt{2}\\y=-2\sqrt{2}\end{matrix}\right.\)
![](https://rs.olm.vn/images/avt/0.png?1311)
100+2x+3x+x/2-56=66
<=> 2x+3x+x/2=66+56-100
<=> 5x+x/2= 22
<=> 5x+0,5x=22
<=>5,5x=22
<=>x= 4
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\left(-66\right)-\left(x-16\right)+150=2x-14\Leftrightarrow-66-x+16+150=2x-14\Leftrightarrow-3x=-114\Leftrightarrow x=38\)
\(\left(-66\right)-\left(x-16\right)+150=2x-14\)
\(-66-x+16+150=2x-14\)
\(-x-2x=66-16-150-14\)
\(-3x=-114\)
\(x=\frac{114}{3}\)
\(x=38\)
![](https://rs.olm.vn/images/avt/0.png?1311)