Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a./ \(\frac{x}{5}=\frac{y}{7}=\frac{z}{4}=\frac{x-y+z}{5-7+4}=\frac{-10}{2}=-5\)
\(\Rightarrow x=-25;y=-35;z=-20\)
b./ \(\frac{x}{5}=\frac{y}{-4}=\frac{z}{-7}=\frac{x+y-z}{5-4-\left(-7\right)}=\frac{-40}{6}=-5\)
\(\Rightarrow x=-25;y=20;z=35\)
a; \(\dfrac{-x}{4}\) = \(\dfrac{-2}{x}\)
-\(x.x\) = -2.4
-\(x^2\) = -8
\(x^2\) = 8
\(\left[{}\begin{matrix}x=-\sqrt{8}\\x=\sqrt{8}\end{matrix}\right.\)
Vậy \(x\in\) {-\(\sqrt{8}\); \(\sqrt{8}\)}
-4/8=-12/24=z/24. Suy ra z=-12
-4/8=-1/2=5/-10=x/-10. Suy ra x=5
-4/8=-1/2=-7/14=-7/y. Suy ra y=14
Ủng hộ mk nha
-4/8=-12/24=z/24. Suy ra z=-12
-4/8=-1/2=5/-10=x/-10. Suy ra x=5
-4/8=-1/2=-7/14=-7/y. Suy ra y=14
Ủng hộ mk nha, mãi chưa đc nào cả !!
\(\frac{-4}{8}\)=\(\frac{x}{-10}\)=\(\frac{-7}{y}\)=\(\frac{z}{-24}\)
+) \(\frac{-4}{8}=\frac{x}{-10}\)
=> x = \(\frac{-10.\left(-4\right)}{8}=5\)
+) \(\frac{-4}{8}=\frac{-7}{y}\)
=> y = \(\frac{-7.8}{-4}\)= 14
+) \(\frac{-4}{8}=\frac{z}{-24}\)
=> z = \(\frac{-24.\left(-4\right)}{8}=12\)
Vậy x=5 ; y=14 ;z=12
\(\frac{3}{x-5}=-\frac{4}{x+2}\)
\(\Leftrightarrow3\left(x+2\right)=-4\left(x-5\right)\)
\(\Leftrightarrow3x+6=-4x+20\)
\(\Leftrightarrow7x=14\)
\(\Leftrightarrow x=2\)
\(\frac{x}{-2}=-\frac{8}{x}\)
\(\Leftrightarrow x^2=16\)
\(\Leftrightarrow x=\pm4\)
\(-\frac{2}{x}=\frac{y}{3}\)
\(\Leftrightarrow xy=-6\)
\(\Leftrightarrow x;y\inƯ\left(-6\right)=\left\{\pm1;\pm2;\pm3;\pm6\right\}\)
Xét bảng
| x | 1 | -1 | 2 | -2 | 3 | -3 | 6 | -1 |
| y | -6 | 6 | -3 | 3 | -2 | 2 | -1 | 6 |
Vậy.................
\(\frac{2x-9}{240}=\frac{39}{80}\)
\(\Leftrightarrow2x-9=\frac{240.39}{80}\)
\(\Leftrightarrow2x-9=117\)
\(\Leftrightarrow2x=126\)
\(\Leftrightarrow x=63\)
Ta có : \(\frac{-4}{8}=\frac{-1}{2}\)
+) \(\frac{-1}{2}=\frac{x}{-10}\Rightarrow x.2=-1.\left(-10\right)\)
\(\Rightarrow x.2=10\Rightarrow x=10\div2=5\in Z\)
+) \(\frac{-1}{2}=\frac{-7}{y}\Rightarrow-1.y=-7.2\)
\(\Rightarrow-1.y=-14\Rightarrow-y=-14\Rightarrow y=14\in Z\)
+) \(\frac{-1}{2}=\frac{z}{-24}\Rightarrow z.2=-1.\left(-24\right)\)
\(\Rightarrow z.2=24\Rightarrow z=24\div2=12\in Z\)
Vậy x = 5 ; y = 14 ; z = 12
x = 5
y = 14
z = 1.5
( nhân chéo chia ngang)
\(\dfrac{-4}{8}\) = \(\dfrac{x}{-10}\) = \(\dfrac{-7}{y}\) = \(\dfrac{z}{-3}\)
\(x\) = \(-\dfrac{4}{8}\).(-10) = 5
y = -7 : (-\(\dfrac{4}{8}\)) = 14
z = - \(\dfrac{4}{8}\).(-3) = \(\dfrac{3}{2}\)
Vậy (\(x;y;z\)) = (5; 14; \(\dfrac{3}{2}\))