x.2+x.3+x.5=20090 < . là dấu nhân>
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Rút x chung ra rồi tính nhé, như này:
x(2+3+5) = 20090
Sau đó tính bình thường
a: \(x+6\dfrac{1}{8}=8\)
=>\(x+\dfrac{49}{8}=\dfrac{64}{8}\)
=>\(x=\dfrac{64}{8}-\dfrac{49}{8}=\dfrac{15}{8}\)
b: \(\dfrac{11}{2}\cdot x=\dfrac{1}{5}:\dfrac{1}{3}\)
=>\(x\cdot\dfrac{11}{2}=\dfrac{1}{5}\cdot3=\dfrac{3}{5}\)
=>\(x=\dfrac{3}{5}:\dfrac{11}{2}=\dfrac{3}{5}\cdot\dfrac{2}{11}=\dfrac{6}{55}\)
c: \(x\cdot\dfrac{3}{5}+\dfrac{2}{5}\cdot x=\dfrac{4}{9}+\dfrac{1}{3}\)
=>\(x\left(\dfrac{3}{5}+\dfrac{2}{5}\right)=\dfrac{4}{9}+\dfrac{3}{9}\)
=>\(x\cdot1=\dfrac{7}{9}\)
=>\(x=\dfrac{7}{9}\)
a: \(\left[\left(10-x\right)\cdot2+51\right]:3-2=3\)
=>\(\left[2\left(10-x\right)+51\right]:3=5\)
=>\(\left[2\left(10-x\right)+51\right]=15\)
=>\(2\left(10-x\right)=15-51=-36\)
=>10-x=-36/2=-18
=>\(x=10-\left(-18\right)=10+18=28\)
b: \(\left(x-12\right)-15=20-\left(17+x\right)\)
=>\(x-12-15=20-17-x\)
=>\(x-27=3-x\)
=>\(2x=30\)
=>\(x=\dfrac{30}{2}=15\)
c: \(720-\left[41-\left(2x-5\right)\right]=2^3\cdot5\)
=>\(720-\left[41-2x+5\right]=8\cdot5=40\)
=>\(\left[41-2x+5\right]=720-40=680\)
=>-2x+46=680
=>-2x=680-46=634
=>\(x=\dfrac{634}{-2}=-317\)
\(5.x+x=15:3+13\\ \Rightarrow\left(5+1\right).x=5+13=18\\ \Rightarrow6x=18\\ \Rightarrow x=\dfrac{18}{6}=3\)
\(\dfrac{2}{3}x+\dfrac{1}{3}x+\dfrac{1}{2}=\dfrac{2}{3}\\ \Rightarrow x\left(\dfrac{2}{3}+\dfrac{1}{3}\right)=\dfrac{2}{3}-\dfrac{1}{2}\\ \Rightarrow x=\dfrac{4}{6}-\dfrac{3}{6}=\dfrac{1}{6}\)
\(\dfrac{2}{5}x+x=\dfrac{3}{2}\\ \Rightarrow x\left(\dfrac{2}{5}+1\right)=\dfrac{3}{2}\\ \Rightarrow x\left(\dfrac{2}{5}+\dfrac{5}{5}\right)=\dfrac{3}{2}\\ \Rightarrow x.\dfrac{7}{5}=\dfrac{3}{2}\\ \Rightarrow x=\dfrac{3}{2}:\dfrac{7}{5}\\ \Rightarrow x=\dfrac{3.5}{7.2}=\dfrac{15}{14}\)
\(5\cdot x+x=15:3+13\)
\(\Rightarrow x\cdot\left(5+1\right)=5+13\)
\(\Rightarrow x\cdot6=18\)
\(\Rightarrow x=\dfrac{18}{6}=3\)
================
\(\dfrac{2}{3}\cdot x+\dfrac{1}{3}\cdot x+\dfrac{1}{2}=\dfrac{2}{3}\)
\(\Rightarrow x\cdot\left(\dfrac{2}{3}+\dfrac{1}{3}\right)=\dfrac{2}{3}-\dfrac{1}{2}\)
\(\Rightarrow x\cdot1=\dfrac{1}{6}\)
\(\Rightarrow x=\dfrac{1}{6}\)
=============
\(\dfrac{2}{5}\cdot x+x=\dfrac{3}{2}\)
\(\Rightarrow x\cdot\left(\dfrac{2}{5}+1\right)=\dfrac{3}{2}\)
\(\Rightarrow x\cdot\dfrac{7}{5}=\dfrac{3}{2}\)
\(\Rightarrow x=\dfrac{3}{2}:\dfrac{7}{5}\)
\(\Rightarrow x=\dfrac{15}{14}\)
2^x+2 *3^x+1*5^x=10800
2^x*2^2*3^x*2*5^x=10800
(2*3*5)^x*12=10800
30^x=10800
\(1.\) \(-12\left(x-5\right)+7\left(3-x\right)=5\)
\(=>-12x+60+21-7x=5\)
\(=>-12x+81-7x=5\)
\(=>-12x-7x+81=5\)
\(=>-19x+81=5\)
\(=>-19x=-76\)
\(=>x=4\)
\(2.\) \(\left(x-2\right).\left(x+15\right)=0\)
\(=>\left[\begin{matrix}x-2=0\\x+15=0\end{matrix}\right.=>\left[\begin{matrix}x=2\\x=-15\end{matrix}\right.\)
\(3.\) \(\left(7-x\right).\left(x+19\right)=0\)
\(=>\left[\begin{matrix}7-x=0\\x+19=0\end{matrix}\right.=>\left[\begin{matrix}x=7\\x=-19\end{matrix}\right.\)
\(4.\) \(\left|x\right|< 3\)
Xét: x là số dương => x < 3
Xét: x là số âm => x < -3
1: =>-12x+60+21-7x=5
=>-19x=-76
hay x=4
2: =>x-2=0 hoặc x+15=0
=>x=2 hoặc x=-15
3: =>7-x=0 hoặc x+19=0
=>x=7 hoặc x=-19