0.5 x X + X : 4 x 6 + X : 2 x 4 = 8
1. Giải các phương trình
b) 3+ (x-5)=2(3x-2) c) 2(x-0.5)+3=0.25(4x-1)
d) 2(x-\(\dfrac{1}{4}\))-4=-6(-\(\dfrac{1}{3}\)x+0.5)+2
b) Ta có: \(3+\left(x-5\right)=2\left(3x-2\right)\)
\(\Leftrightarrow3+x-5=6x-4\)
\(\Leftrightarrow x-2-6x+4=0\)
\(\Leftrightarrow-5x+2=0\)
\(\Leftrightarrow-5x=-2\)
\(\Leftrightarrow x=\dfrac{2}{5}\)
Vậy: \(S=\left\{\dfrac{2}{5}\right\}\)
c) Ta có: \(2\left(x-0.5\right)+3=0.25\left(4x-1\right)\)
\(\Leftrightarrow2x-1+3=x-\dfrac{1}{4}\)
\(\Leftrightarrow2x+2-x+\dfrac{1}{4}=0\)
\(\Leftrightarrow x+\dfrac{9}{4}=0\)
\(\Leftrightarrow x=-\dfrac{9}{4}\)
Vậy: \(S=\left\{-\dfrac{9}{4}\right\}\)
d) Ta có: \(2\left(x-\dfrac{1}{4}\right)-4=-6\left(-\dfrac{1}{3}x+0.5\right)+2\)
\(\Leftrightarrow2x-\dfrac{1}{2}-4=2x-3+2\)
\(\Leftrightarrow2x-\dfrac{9}{2}=2x-1\)
\(\Leftrightarrow2x-2x=-1+\dfrac{9}{2}\)
\(\Leftrightarrow0x=\dfrac{7}{2}\)(vô lý)
Vậy: \(S=\varnothing\)
b.
→ -2 + x = 6x - 4
→ -2 + 4 = 6x - x
→ 2 = 5x
→ x = \(\dfrac{2}{5}\)
Vậy, phương trình có tập nghiệm S = {\(\dfrac{2}{5}\)}
dang 2
1/_6,4x+(-2,4)x=1,2
2/_2.3/4:x3.1/7:0,01
3/_3/4+1/4:x=1
4/_(x-2/3)(x+1/4)=0
5/_|x+4/5|=0
6/_|x+3/4|-3/4=0
7/_1,6-|x-0,4|=0.5
8/_(x-1/2)^2+=0
9/_(x-3)^3=8
10/_(x+1/2)^2=1/25
11/_-3^x/81=-27
12/_a/x/15=-60/x
b/x/27=2/36
9: =>x-3=2
=>x=5
10: =>x+1/2=1/5 hoặc x+1/2=-1/5
=>x=-7/10 hoặc x=-3/10
12:
a: =>x^2=900
=>x=30 hoặc x=-30
b: =>x=1/18*27=3/2
7: =>|x-0,4|=1,1
=>x-0,4=1,1 hoặc x-0,4=-1,1
=>x=1,5 hoặc x=-0,7
a ) 4 phần X = -Y phần 6 = 0.5
b) x phần -3 = 4 phần y = 8 phần 12
a) \(\frac{4}{X}=-\frac{y}{6}=0,5\Rightarrow\hept{\begin{cases}X=4:0,5=8\\y=0,5.\left(-6\right)=-3\end{cases}}\)
b) \(\frac{x}{-3}=\frac{4}{y}=\frac{8}{12}=\frac{2}{3}\Rightarrow\hept{\begin{cases}x=\frac{2}{3}.\left(-3\right)=-2\\y=4:\frac{2}{3}=6\end{cases}}.\)
a. \(\frac{4}{x}=-\frac{y}{6}=0,5\)
\(\rightarrow\hept{\begin{cases}\frac{4}{x}=0,5\rightarrow x=8\\-\frac{y}{6}=0,5\rightarrow y=-3\end{cases}}\)
b. \(\frac{x}{-3}=\frac{4}{y}=\frac{8}{12}=\frac{2}{3}\)
\(\rightarrow\hept{\begin{cases}\frac{x}{-3}=\frac{2}{3}\rightarrow x=-2\\\frac{4}{y}=\frac{2}{3}\rightarrow y=6\end{cases}}\)
2.5 x 9.5 x 4 + 20 x 9.5 x 0.5 + 9.5 x 8 x 1.25
\(2,5\) x \(9,5\) x \(4+20\) x \(9,5\) x \(0,5\) +\(9,5\) x \(8\) x \(1,25\)
\(=9,5\) x ( \(2,5\) x \(4+20\) x \(0,5\) + \(8\) x \(1,25\) )
\(=9,5\) x \(30\)
\(=285\)
2.5 x 9.5 x 4 + 20 x 9.5 x 0.5 + 9.5 x 8 x 1.25
=9.5*10+9.5*10+9.5+10
=9.5*(10+10+10)
=9.5*30
=2850
`2,5xx9,5xx4+20xx9,5xx0,5+9,5xx8xx1,25`
`=9,5xx10+9,5xx10+9,5xx10`
`=9,5xx(10+10+10)`
`=9,5xx30`
`=285`
= 9,5 x (2,5 + 4+20+0,5+8+1,25)
=9,5x36,25
=344,375
tìm x biết
a,3/35-(3/5+x)=2/7
b,5/6+1/6:x=3/4
c,|x-3 4/7|=-0.5
tìm x biết
a,3/35-(3/5+x)=2/7
b,5/6+1/6:x=3/4
c,|x-3 4/7|=-0.5
\(a,\frac{3}{35}-\left[\frac{3}{5}+x\right]=\frac{2}{7}\)
\(\Rightarrow\frac{3}{5}+x=\frac{3}{35}-\frac{2}{7}\)
\(\Rightarrow\frac{3}{5}+x=\frac{3}{35}-\frac{2\cdot5}{35}\)
\(\Rightarrow\frac{3}{5}+x=\frac{3}{35}-\frac{10}{35}=\frac{-7}{35}\)
\(\Rightarrow x=\frac{-7}{35}-\frac{3}{5}=\frac{-7}{35}-\frac{3\cdot7}{35}=\frac{-7}{35}-\frac{21}{35}=\frac{-28}{35}=\frac{-4}{5}\)
\(b,\frac{5}{6}+\frac{1}{6}:x=\frac{3}{4}\)
\(\Rightarrow\frac{1}{6}:x=\frac{3}{4}-\frac{5}{6}\)
\(\Rightarrow\frac{1}{6}:x=\frac{18}{24}-\frac{20}{24}\)
\(\Rightarrow\frac{1}{6}:x=\frac{-2}{24}\)
\(\Rightarrow x=\frac{1}{6}:\frac{-2}{24}=\frac{1}{6}:\frac{-1}{12}=\frac{12}{-6}=\frac{-12}{6}=-2\)
\(c,\left|x-3\frac{4}{7}\right|=-0,5\)
Vì \(\left|x-3\frac{4}{7}\right|\ge0\)mà \(-0,5< 0\)nên \(x\in\varnothing\)
Vậy không có giá trị x thỏa mãn
a) 3/35-(3/5+x)=2/7
<=> 3/5+x=3/35-2/7
<=> 3/5+x=3/35-10/35
<=> 3/5+x=-7/35
<=> 3/5+x=-1/5
<=> x=-1/5-3/5
<=> x=-4/5
Vậy x=-4/5
2.5 x 9.5 x 4 + 20 x 9.5 x 0.5 + 9.5 x 8 x 1.25
lời giải rõ ràng
\(x+15\%.x=115\)
\(|x+8|=10\)
\(\frac{4}{x}=\frac{-y}{6}=0.5\)
|x + 8| = 10
=> x + 8 = 10 hoặc x + 8 = -10
=> x = 2 hoặc x = -18
vậy_
\(x+15\%x=115\)
\(\Leftrightarrow x+\frac{15}{100}x=115\)
\(\Leftrightarrow x+\frac{3}{20}x=115\)
\(\Leftrightarrow x\left(1+\frac{3}{20}\right)=115\)
\(\Leftrightarrow x\left(\frac{20}{20}+\frac{3}{20}\right)=115\)
\(\Leftrightarrow\frac{23}{20}x=115\)
\(\Leftrightarrow x=115\div\frac{23}{20}\)
\(\Leftrightarrow x=115\times\frac{20}{23}\)
\(\Leftrightarrow x=\frac{2300}{23}=100\)
\(\frac{4}{x}=\frac{-y}{6}=0,5\)
\(\Rightarrow\hept{\begin{cases}\frac{4}{x}=0,5\Leftrightarrow x=8\\\frac{-y}{6}=0,5\Leftrightarrow y=-3\end{cases}}\)
Vậy \(\left(x,y\right)\in\left\{\left(8,-3\right)\right\}\)