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a) \(\dfrac{2}{3}x-\dfrac{1}{2}=\dfrac{1}{10}\)
\(\dfrac{2}{3}x=\dfrac{1}{10}+\dfrac{1}{2}=\dfrac{3}{5}\)
\(x=\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{9}{10}\)
b) \(\dfrac{39}{7}:x=13\)
\(x=\dfrac{\dfrac{39}{7}}{13}=\dfrac{3}{7}\)
c) \(\left(\dfrac{14}{5}x-50\right):\dfrac{2}{3}=51\)
\(\dfrac{14}{5}x-50=51\cdot\dfrac{2}{3}=34\)
\(\dfrac{14}{5}x=34+50=84\)
\(x=\dfrac{84}{\dfrac{14}{5}}=30\)
d) \(\left(x+\dfrac{1}{2}\right)\left(\dfrac{2}{3}-2x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{2}{3}-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)
e) \(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{5}{12}\)
\(\dfrac{1}{6}x=\dfrac{5}{12}\)
\(x=\dfrac{5}{12}:\dfrac{1}{6}=\dfrac{5}{2}\)
g) \(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\dfrac{11}{5}-\dfrac{3}{7}=-2\)
\(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\cdot\dfrac{11}{5}=-2+\dfrac{3}{7}=-\dfrac{11}{7}\)
\(x\cdot\dfrac{44}{7}+\dfrac{3}{7}=-\dfrac{11}{7}:\dfrac{11}{5}=-\dfrac{5}{7}\)
\(\dfrac{44}{7}x=-\dfrac{5}{7}-\dfrac{3}{7}=-\dfrac{8}{7}\)
\(x=-\dfrac{8}{7}:\dfrac{44}{7}=-\dfrac{2}{11}\)
h) \(\dfrac{13}{4}x+\left(-\dfrac{7}{6}\right)x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{25}{12}\)
\(x=1\)
Mỏi tay woa bn làm nốt nha!!
a) x+30%x=-1.31
=> 100%x+30%x=-1.31
=>x.(100%+30%)=-1.31
=>x.13/10=-1.31=-1.31:13/10=-131/130
b) (x-1/2):1/3+5/7=9+5/7
=>(x-1/2).3+5/7=68/7
=>(x-1/2).3=68/7-5/7=9
=>x-1/2=9:3=3
=>x=3+1/2=3 1/2( hỗn số)
c) 1/2x-3/4=14/9.3/7
=>1/2x-3/4=2/3
=>1/2x=2/3+3/4=17/12
x=17/12:1/2=17/12.2=17/6
d) - 5/6 -x = 7/12+ -1/3
=>- 5/6 -x = 7/12+ -4/12=1/4
=> x = -5/6 -1/4=-13/12
e) x + 3/-15 = 1/3
=> x= 1/3 - -3/15 =1/3+3/15
=> x=5/15 + 3/15=8/15
f) (4,5 -2 x). (-1 4/7)=11/14
=> 4,5 -2x=11/14 : -3/7=11/14. -7/3=-11/6
=>-2x=-11/6-9/2= -11/6 -27/6 =-19/3
=>x= -19/3: -2x=19/6
Chúc bn thi HKII tốt!!!
tao là N nè kqua phần a ra 20/3, phần b là 2.5 còn phần c tao làm rồi nhưng không chắc
a) x/3 - 1/2 = 1/5
<=> x/3 = 1/5 + 1/2
<=> x/3 = 7/10
<=> 10x = 3 . 7
<=> 10x = 21
<=> x = 21 : 10
<=> x = 2,1
Vậy x = 2,1
b) x/5 + 1/2 = 6/10
<=> x/5 = 6/10 - 1/2
<=> x/5 = 6/10 - 5/10
<=> x/5 = 1/10
<=> 10x = 5
<=> x = 5 : 10
<=> x = 0,5
Vậy x = 0,5
c) x + 3/15 = 1/3
<=> x = 1/3 - 3/15
<=> x = 5/15 - 3/15
<=> x = 2/15
Vậy x = 2/15
d) x - 14/4 = 1/4
<=> x = 1/4 + 14/4
<=> x = 15/4
Vậy x = 15/4
Cho mình câu chả lời sớm nhất vào 4h30 chiều ngày 28/9/2021
a) \(3\frac{1}{3}\left(3\frac{1}{4}+2x\right)=6\frac{2}{3}\)
\(3\frac{1}{3}\times3\frac{1}{4}+2x=6\frac{2}{3}\)
\(10\frac{5}{6}+2x=6\frac{2}{3}\)
\(2\times x=6\frac{2}{3}+10\frac{5}{6}=17,5\)
\(x=17,5\div2=8,75\)
Vậy x = 8,75
b) \(x-25\%x=\frac{6}{11}\left(\frac{1}{2}+\frac{3}{4}-\frac{1}{3}\right)\)
\(x-\frac{25}{100}x=\frac{6}{11}\left(\frac{1}{2}+\frac{3}{4}-\frac{1}{3}\right)\)
\(x-\frac{1}{4}\times x=\frac{6}{11}\times1\frac{7}{12}=\frac{19}{22}\)
\(x\times x=\frac{19}{22}+\frac{1}{4}=\frac{49}{44}\)
\(\Rightarrow2x\left(x\times x\right)=\frac{49}{44}\)
\(x=\frac{49}{44}\div2=\frac{49}{88}\)
Vậy x = \(\frac{49}{88}\)
c) \(\left(4,5-2x\right)\times1\frac{4}{7}=\frac{11}{14}\)
\(4,5-2x\times1\frac{4}{7}=\frac{11}{14}\)
\(-2x\times1\frac{4}{7}=\frac{11}{14}-4,5=-3\frac{5}{7}\)
\(-2\times x=-3\frac{5}{7}\div1\frac{4}{7}=-2\frac{4}{11}\)
\(x=-2\frac{4}{11}\div\left(-2\right)=1\frac{2}{11}\)
Vậy x = \(1\frac{2}{11}\)
d) \(-3^2-|2x+3|=4\)
\(9-|2x+3|=4\)
\(-|2x+3|=4-9=-5\)
\(-|2x|=-5-|3|=-8\)
\(-|x|=-8\div2=-4\)
\(-x=4\Rightarrow x=-4\)
Vậy x = -4 (-x được xem là số đối của x)