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\(\left(20x-x\right)-\left(-14-2x\right)+\left(-35-x\right)=5-3x\)
\(20-x+14+2x-35-x=5-3x\)
\(-1=5-3x\)
\(3x=5+1\)
\(3x=6\)
\(x=6:3\)
\(x=2\)
( 20 - x ) - ( -14 - 2x ) + ( -35 - x ) = 5 - 3x
20 - x + 14 + 2x - 35 - x =5-3x
20 - x + 14 + 2x - 35 - x + 3x =5
( -x + 2x - x + 3x ) + ( 20 + 14 - 35 ) = 5
3x - 1 = 5
3x = 5 + 1
3x = 6
x = 6 : 3
x = 2
Vậy x = 2
a,\(\left(\frac{7}{5}-2x\right).\frac{40}{20}=\frac{8}{14}\)
\(\Rightarrow\left(\frac{7}{5}-2x\right).2=\frac{4}{7}\)
\(\Rightarrow\frac{7}{5}-2x=\frac{4}{7}:2\)
\(\Rightarrow\frac{7}{5}-2x=\frac{2}{7}\)
\(\Rightarrow2x=\frac{7}{5}-\frac{2}{7}\)
\(\Rightarrow2x=\frac{39}{35}\)
\(\Rightarrow x=\frac{39}{35}:2\)
\(\Rightarrow x=\frac{39}{70}\)
b, \(\frac{7}{2}.x-20\%.x=-4\)
\(\Rightarrow x\left(\frac{7}{2}-20\%\right)=-4\)
\(\Rightarrow x\left(\frac{7}{2}-\frac{1}{5}\right)=-4\)
\(\Rightarrow x\frac{7}{10}=-4\)
\(\Rightarrow x=-4:\frac{7}{10}\)
\(\Rightarrow x=-\frac{40}{7}\)
a: =>x/27+1=-2/3
=>x/27=-5/3
=>x=-45
b: \(\Leftrightarrow x-4=\dfrac{2}{5}:\dfrac{20}{21}=\dfrac{2}{5}\cdot\dfrac{21}{20}=\dfrac{42}{100}=\dfrac{21}{50}\)
=>x=221/50
c: \(\Leftrightarrow x+\dfrac{2}{3}=\dfrac{4}{60}=\dfrac{1}{15}\)
=>x=1/15-2/3=1/15-10/15=-9/15=-3/5
d: \(\Leftrightarrow x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{15}{14}\cdot\dfrac{21}{20}\)
=>\(x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{3}{2}\cdot\dfrac{3}{4}=\dfrac{1}{5}-\dfrac{9}{8}=\dfrac{-37}{40}\)
=>x=-37/24
e: =>-3/7x=84/45
=>x=-196/45
f: =>11/10x=-2/3
=>x=-20/33
Bài 1:
a. $(-20)+x=-30$
$x-20=-30$
$x=-30+20=-(30-20)=-10$
b.
$(-10)-x=-20$
$x=(-10)-(-20)=-10+20=20-10=10$
c. Đề sai. Bạn xem lại.
d.
$x+(-3)=-7$
$x=-7-(-3)=-7+3=-(7-3)=-4$
e.
$x-(-5)=-9$
$x=(-9)+(-5)=-14$
f.
$x(-11)=12$
$x=\frac{12}{-11}=\frac{-12}{11}$
h.
$2x-10=20$
$2x=20+10=30$
$x=30:2=15$
l.
$4x-8=-8$
$4x=-8+8=0$
$x=0:4=0$
k.
$-12-(-2)x=-8$
$(-2)x=-12-(-8)=-12+8=-(12-8)=-4$
$x=(-4):(-2)=2$
Bài 2:
a. $-20-(10-x)=-3$
$10-x=-20-(-3)=-20+3=-(20-3)=-17$
$x=10-(-17)=10+17=27$
b.
$14+(14-x)=-2$
$14-x=-2-14=-16$
$x=14-(-16)=14+16=30$
c.
$-15-(x-3)=-7$
$x-3=-15-(-7)=-15+7=-8$
x=-8+3=-5$
d.
$(x+4)+(-20)=-8$
$x+4=-8-(-20)=-8+20=12$
$x=12-4=8$
e.
$-2x-2=-4$
$-2x=-4+2=-2$
$x=(-2):(-2)=1$
f.
$-2x+4=-4$
$-2x=-4-4=-8$
$x=(-8):(-2)=4$
l.
$-12-(-2)x=-2-4=-6$
$(-2)x=-12-(-6)=-12+6=-6$
$x=(-6):(-2)=3$
\(2x-20:5=14\)
\(\Rightarrow2x-4=14\)
\(\Rightarrow2x=14+4\)
\(\Rightarrow2x=18\)
\(\Rightarrow x=18:2\)
\(\Rightarrow x=9\)
Vậy x = 9
Chúc em học tốt nha!^^
c) \(\left(34-2x\right)\left(2x-6\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}34-2x=0\\2x-6-0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}2x=34\\2x=6\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=17\\x=3\end{matrix}\right.\)
d) \(\left(2019-x\right)\left(3x-12\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}2019-x=0\\3x-12=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2019\\3x=12\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2019\\x=4\end{matrix}\right.\)
e) \(57\left(9x-27\right)=0\)
\(\Rightarrow9x-27=0\)
\(\Rightarrow9\left(x-3\right)=0\)
\(\Rightarrow x-3=0\)
\(\Rightarrow x=3\)
f) \(25+\left(15-x\right)=30\)
\(\Rightarrow25+15-x=30\)
\(\Rightarrow40-x=30\)
\(\Rightarrow x=40-30\)
\(\Rightarrow x=10\)
g) \(43-\left(24-x\right)=20\)
\(\Rightarrow43-24+x=20\)
\(\Rightarrow19+x=20\)
\(\Rightarrow x=20-19\)
\(\Rightarrow x=1\)
h) \(2\left(x-5\right)-17=25\)
\(\Rightarrow2\left(x-5\right)=17+25\)
\(\Rightarrow x-5=21\)
\(\Rightarrow x=21+5\)
\(\Rightarrow x=26\)
i) \(3\left(x+7\right)-15=27\)
\(\Rightarrow3\left(x+7\right)=27+15\)
\(\Rightarrow x+7=14\)
\(\Rightarrow x=14-7\)
\(\Rightarrow x=7\)
j) \(15+4\left(x-2\right)=95\)
\(\Rightarrow4\left(x-2\right)=95-15\)
\(\Rightarrow4\left(x-2\right)=80\)
\(\Rightarrow x-2=20\)
\(\Rightarrow x=20+2\)
\(\Rightarrow x=22\)
k) \(20-\left(x+14\right)=5\)
\(\Rightarrow x+14=20-5\)
\(\Rightarrow x+14=15\)
\(\Rightarrow x=15-14\)
\(\Rightarrow x=1\)
l) \(14+3\left(5-x\right)=27\)
\(\Rightarrow3\left(5-x\right)=27-14\)
\(\Rightarrow3\left(5-x\right)=13\)
\(\Rightarrow5-x=\dfrac{13}{3}\)
\(\Rightarrow x=5-\dfrac{13}{3}\)
\(\Rightarrow x=\dfrac{2}{3}\)
2x+20=-22
=> 2x = -22 - 20
=> 2x = -42
=> x = -42 : 2
=> x = -21
Vậy x = -21
2x+20=-22
2x=-22-20
2x=-42
x=-42:2
x=-21
-(-30)-(-x)=13
30+x=13
x=13-30
x=-17
-(-x)+14=12
x+14=12
x=12-14
x=-2
x+20=-(-23)
x+20=23
x=23-20
x=3
15-x+17=-(-6)+|-12|
15+17+x=6+12
32+x=18
x=18-32
x=-14
-|-5|-(-x)+4=3-(-25)
-5+x+4=3+25
-5+4+x=28
-1x=28
x=28:(-1)
x=-28
2x = -14 + 20
2x = 6
x= 3
2x - (-20) = 14
2x = 14 + (-20)
2x = -6
x =-6:2
x = -3