Tìm x bt : 4/5 + 5/7 . x = 1/6
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Lời giải:
a.
$\frac{2}{3}x-\frac{7}{6}=\frac{12}{7}-\frac{1}{2}=\frac{17}{14}$
$\frac{2}{3}x=\frac{17}{14}+\frac{7}{6}=\frac{50}{21}$
$x=\frac{50}{21}: \frac{2}{3}=\frac{25}{7}$
b.
$(1\frac{1}{2}+\frac{5}{3}-\frac{1}{6}):x=\frac{3}{4}-\frac{1}{2}$
$3:x=\frac{1}{4}$
$x=3: \frac{1}{4}=12$
1: =>5(2x+6)=40
=>2x+6=8
=>2x=2
=>x=1
2: =>12-(x+3)=256:64=4
=>(x+3)=8
=>x=5
3: =>2x-1=3 hoặc 2x-1=-3
=>x=2 hoặc x=-1
4: \(\Leftrightarrow3^{x+2017}=3^{2015}\)
=>x+2017=2015
=>x=-2
a. \(x-\frac{3}{7}:\frac{9}{14}=-\frac{7}{6}\Rightarrow x-\frac{2}{3}=-\frac{7}{6}\Rightarrow x=-\frac{1}{2}\)
b. \(\frac{3}{4}+\frac{1}{4}x=\frac{5}{8}\Rightarrow\frac{1}{4}x=-\frac{1}{8}\Rightarrow x=-\frac{1}{2}\)
c. \(\left|4x-1\right|-\frac{1}{2}=3\Rightarrow\left|4x-1\right|=\frac{7}{2}\Leftrightarrow\orbr{\begin{cases}4x-1=\frac{7}{2}\\4x-1=-\frac{7}{2}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{9}{8}\\x=-\frac{5}{8}\end{cases}}}\)
d. \(25\%x+x=-1,25\Rightarrow125\%x=-1,25\Rightarrow\frac{5}{4}x=-\frac{5}{4}\Rightarrow x=-1\)
a) Ta có: 36-x=44
nên x=36-44=-8
Vậy: x=-8
b) Ta có: \(\dfrac{5}{6}-x=\dfrac{7}{4}-0.75-3\)
\(\Leftrightarrow\dfrac{5}{6}-x=\dfrac{7}{4}-\dfrac{3}{4}-3=1-3=-2\)
hay \(x=\dfrac{5}{6}+2=\dfrac{17}{6}\)
a) 36-x=44 b) 5/6-x=7/4-0,75-3
=> x= 36-44 => 5/6-x= -2
=> x= -8 => x= 5/6-(-2)
=> x=17/6
Câu 1:
a) \(\frac{3}{2}.\frac{4}{5}-x=\frac{2}{3}\)
\(\frac{6}{5}-x=\frac{2}{3}\)
\(x=\frac{8}{15}\)
b) \(\frac{6}{7}:\frac{1}{2}.\frac{3}{4}-\frac{5}{8}=\frac{37}{56}\)
Câu 2:
Gọi số có hai chữ số cần tìm là: ab
ta có: ab2 = ab + 92
=> a x 100 + b x 10 + 2 = a x 10 + b + 92
=> a x 90 + b x 9 = 90
9 x ( a x 10 + b) = 90
a x 10 + b = 90 : 9
a x 10 + b = 10 = 1 x 10 + 0
=> a = 1; b = 0
KL: ab = 10
Câu 1 :
a) \(\frac{3}{2}\times\frac{4}{5}-x=\frac{2}{3}\)
\(\Rightarrow\frac{6}{5}-x=\frac{2}{3}\)
\(\Rightarrow x=\frac{6}{5}-\frac{2}{3}\)
\(\Rightarrow x=\frac{8}{15}\)
b) Ko rõ đề :)
Câu 2 :
Gọi số cần tìm là \(\overline{ab}\), ta có :
\(\overline{ab2}-\overline{ab}=92\)
\(\Rightarrow\overline{ab}\times10+2-\overline{ab}=92\)
\(\Rightarrow\overline{ab}\times9+2=92\)
\(\Rightarrow\overline{ab}\times9=90\)
\(\Rightarrow\overline{ab}=90:9\)
\(\Rightarrow\overline{ab}=10\)
Học tốt # ^-<
-1/2 .x + 2/3 : (-4/5) = 3/5 - 5/6
-1/2.x - 5/6 = -7/30
-1/2.x = -7/30 + 5/6
-1/2.x = 3/5
x = 3/5 : (-1/2)
x = 6/5
\(\frac{x-1}{x+5}=\frac{6}{7}\)
\(\left(x-1\right).7=\left(x+5\right).6\)
\(7x-7=6x+30\)
\(7x-6x=30+7\)
\(x=37\)
\(\frac{x-1}{x+5}=\frac{6}{7}\)
=>(x-1).7=(x+5).6
=>x.7-7=x.6+30
=>x.7-x.6=30+7
=>x=37
\(\frac{4}{5}+\frac{5}{7}x=\frac{1}{6}\)
\(\frac{5}{7}x=-\frac{19}{30}\)
\(x=-\frac{133}{150}\)
Study well : xin đừng đáp đá nha
\(\frac{4}{5}+\frac{5}{7}.x=\frac{1}{6}\)
\(\frac{5}{7}.x=\frac{1}{6}-\frac{4}{5}\)
\(\frac{5}{7}.x=\frac{5}{30}-\frac{24}{30}\)
\(\frac{5}{7}.x=-\frac{19}{30}\)
\(x=-\frac{19}{30}:\frac{5}{7}\)
\(x=-\frac{19}{30}.\frac{7}{5}\)
\(x=-\frac{133}{150}\)
Vậy \(x=-\frac{133}{150}\)
Chúc bạn học tốt !!!