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\(a/\frac{7}{9}-\frac{x}{3}=\frac{1}{9}\)
\(\Rightarrow\frac{x}{3}=\frac{7}{9}-\frac{1}{9}\)
\(\Rightarrow\frac{x}{3}=\frac{2}{3}\)
\(\Rightarrow x=2\)
Vậy \(x=2\)
\(b/\frac{1}{x}-\frac{-2}{15}=\frac{7}{15}\)
\(\Rightarrow\frac{1}{x}=\frac{7}{15}+\frac{-2}{15}\)
\(\Rightarrow\frac{1}{x}=\frac{1}{3}\)
\(\Rightarrow x=3\)
Vậy \(x=3\)
\(c/\frac{-11}{14}-\frac{-4}{x}=\frac{-3}{14}\)
\(\Rightarrow\frac{-4}{x}=\frac{-11}{14}-\frac{-3}{14}\)
\(\Rightarrow\frac{-4}{x}=\frac{-4}{7}\)
\(\Rightarrow x=7\)
Vậy \(x=7\)
\(d/\frac{x}{21}-\frac{2}{3}=\frac{5}{21}\)
\(\Rightarrow\frac{x}{21}=\frac{5}{21}+\frac{2}{3}\)
\(\Rightarrow\frac{x}{21}=\frac{19}{21}\)
\(\Rightarrow x=19\)
Vậy \(x=19\)
#Mạt Mạt#
\(a)x+30\%x=-1,31\)
\(\Leftrightarrow x+\frac{3x}{10}=-1,31\)
\(\Leftrightarrow10x+3x=-13,1\)
\(\Leftrightarrow13x=-13,1\Leftrightarrow x=-\frac{131}{130}\)
\(b)\left(x-\frac{1}{2}\right):\frac{1}{3}+\frac{5}{7}=9\frac{5}{7}\)
\(\Leftrightarrow\frac{2x-1}{2}.3+\frac{5}{7}=\frac{68}{7}\)
\(\Leftrightarrow\frac{6x-3}{2}=\frac{63}{7}\)
\(\Leftrightarrow\frac{6x-3}{2}=9\)
\(\Leftrightarrow6x-3=18\)
\(\Leftrightarrow x=\frac{7}{2}\)
a) 2x . 4 = 128
2x = 128 : 4
2x = 32
2x = 25
=> x = 5
b) 2x . 24 = 26
=> x + 4 = 6
x = 6 - 4
x = 2
c) 5x + x = 39 - 311 : 39
6x = 39 - 32
6x = 39 - 9
6x = 30
x = 30 : 6
x = 5
d) 9x - 1 = 81
9x - 1 = 92
=> x - 1 = 2
x = 2 + 1
x = 3
e) 6x = 521 : 519 + 3 . 22 - 70
6x = 52 + 3 . 4 - 1
6x = 25 + 12 - 1
6x = 37 - 1
6x = 36
x = 36 : 6
x = 6
1)
a)
\(\frac{-5}{6}.\frac{120}{25}< x< \frac{-7}{15}.\frac{9}{14}\)
\(\frac{-1}{1}.\frac{20}{5}< x< \frac{-1}{5}.\frac{3}{2}\)
\(\frac{-20}{5}< x< \frac{-3}{10}\)
\(\frac{-40}{10}< x< \frac{-3}{10}\)
\(\Rightarrow Z\in\left\{-4;-5;-6;-7;-8;-9;-10;...;-39\right\}\)
a
\(5\frac{4}{7}:x+=13\)
\(\frac{39}{7}:x=13\)
\(x=\frac{39}{7}:13\)
\(x=\frac{3}{7}\)
\(\frac{4}{7}x=\frac{9}{8}-0,125\)
\(\frac{4}{7}x=1\)
\(x=1:\frac{4}{7}\)
\(x=\frac{7}{4}=1\frac{3}{4}\)
a) \(\left|-7^{50}\right|:7^{48}-\left|6^2\right|\)
\(=7^{50}:7^{48}-6^2\)
\(=7^{50-48}-6^2\)
\(=7^2-6^2\)
\(=49-36\)
\(=13\)
b) \(3x-9=\left|-21\right|\)
\(\Rightarrow3x-9=21\)
\(\Rightarrow3x=21+9\)
\(\Rightarrow3x=30\)
\(\Rightarrow x=30:3\)
\(\Rightarrow x=10\)
Vậy \(x=10\)
c) \(\left|x\right|-3=7\)
\(\Rightarrow\left|x\right|=7+3\)
\(\Rightarrow\left|x\right|=10\)
\(\Rightarrow\left[{}\begin{matrix}x=10\\x=-10\end{matrix}\right.\)
Vậy \(x=10\) hoặc \(x=-10\)
d) \(\left|x-4\right|-2=\left|-5\right|\)
\(\Rightarrow\left|x-4\right|-2=5\)
\(\Rightarrow\left|x-4\right|=5+2\)
\(\Rightarrow\left|x-4\right|=7\)
Xét trường hợp 1: \(x-4=7\)
\(\Rightarrow x=7+4\)
\(\Rightarrow x=11\)
Xét trường hợp 2: \(x-4=-7\)
\(\Rightarrow x=-7+4\)
\(\Rightarrow x=-\left(7-4\right)\)
\(\Rightarrow x=-3\)
Vậy \(x=11\) hoặc \(x=-3\)
a) ∣∣−750∣∣:748−∣∣62∣∣|−750|:748−|62|
=750:748−62=750:748−62
=750−48−62=750−48−62
=72−62=72−62
=49−36=49−36
=13=13
b) 3x−9=|−21|3x−9=|−21|
⇒3x−9=21⇒3x−9=21
⇒3x=21+9⇒3x=21+9
⇒3x=30⇒3x=30
⇒x=30:3⇒x=30:3
⇒x=10⇒x=10
Vậy x=10x=10
c) |x|−3=7|x|−3=7
⇒|x|=7+3⇒|x|=7+3
⇒|x|=10⇒|x|=10
⇒[x=10x=−10⇒[x=10x=−10
Vậy x=10x=10 hoặc x=−10x=−10
d) |x−4|−2=|−5||x−4|−2=|−5|
⇒|x−4|−2=5⇒|x−4|−2=5
⇒|x−4|=5+2⇒|x−4|=5+2
⇒|x−4|=7⇒|x−4|=7
Xét trường hợp 1: x−4=7x−4=7
⇒x=7+4⇒x=7+4
⇒x=11⇒x=11
Xét trường hợp 2: x−4=−7x−4=−7
⇒x=−7+4⇒x=−7+4
⇒x=−(7−4)⇒x=−(7−4)
⇒x=−3⇒x=−3
Vậy x=11x=11 hoặc x=−3