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1)[x-128+20] :192=0
x-128+20 = 192
x-128 = 192-20
x-128 = 172
x = 172+128
x = 300
2) bạn nhớ check lại câu này giùm Nhi nha!
3) 460+85.4 = [ x+200] .4
460+ 340 = 4x+ 800
4x+800 = 800
4x = 800-800
4x = 0
x = 0:4
x = 0
1)\(\left(x-280\right):35=56.5\)
\(\left(x-280\right):35=280\)
\(x-280=280.35\)
\(x-280=9800\)
\(x=9800+280\)
\(x=10080\)
2) \(\left(x-128+20\right):192=0\)
\(\Rightarrow\left(x-148\right):192=0\)
\(\Rightarrow x-148=0\)
\(\Rightarrow x=0+148\)
\(\Rightarrow x=148\)
3) \(460+85.4=\left(x+200\right).4\)
\(\Rightarrow\left(x+200\right).4=460+340\)
\(\Rightarrow\left(x+200\right).4=800\)
\(\Rightarrow x+200=800:4=200\)
\(\Rightarrow x+200=200\)
\(\Rightarrow x=200-200=0\)
4) \(x+5.2-\left(32+16.3:16-15\right)=0\)
\(\Rightarrow x+10-\left(32+3-15\right)=0\)
\(\Rightarrow x+10-20=0\)
\(\Rightarrow x+10=20\)
\(\Rightarrow x=20-10=10\)
nha m.n
Giải:
a) \(\dfrac{-5}{8}=\dfrac{x}{16}\)
\(\Rightarrow x=\dfrac{16.-5}{8}=-10\)
\(\dfrac{3x}{9}=\dfrac{2}{6}\)
\(\Rightarrow3x=\dfrac{2.9}{6}=3\)
\(\Rightarrow x=1\)
b) \(\dfrac{x+3}{15}=\dfrac{1}{3}\)
\(\Rightarrow x+3=\dfrac{1.15}{3}=5\)
\(\Rightarrow x=2\)
\(\dfrac{6}{2x+1}=\dfrac{2}{7}\)
\(\Rightarrow2x+1=\dfrac{6.7}{2}=21\)
\(\Rightarrow x=10\)
c) \(\dfrac{4}{x-6}=\dfrac{y}{24}=\dfrac{-12}{18}\)
\(\Rightarrow\dfrac{4}{x-6}=\dfrac{-12}{18}\)
\(\Rightarrow x-6=\dfrac{18.4}{-12}=-6\)
\(\Rightarrow x=0\)
\(\Rightarrow\dfrac{y}{24}=\dfrac{-12}{18}\)
\(\Rightarrow y=\dfrac{-12.24}{18}=-16\)
\(\dfrac{3-x}{-12}=\dfrac{16}{y+1}=\dfrac{192}{-72}\)
\(\Rightarrow\dfrac{3-x}{-12}=\dfrac{192}{-72}\)
\(\Rightarrow3-x=\dfrac{192.-12}{-72}=32\)
\(\Rightarrow x=-29\)
\(\Rightarrow\dfrac{16}{y+1}=\dfrac{192}{-72}\)
\(\Rightarrow y+1=\dfrac{16.-72}{192}=-6\)
d) \(\dfrac{-2}{3}< \dfrac{x}{5}< \dfrac{-1}{6}\)
\(\Rightarrow\dfrac{-20}{30}< \dfrac{6x}{30}< \dfrac{-5}{30}\)
\(\Rightarrow6x\in\left\{-18;-12;-6\right\}\)
\(\Rightarrow x\in\left\{-3;-2;-1\right\}\)
\(\dfrac{-1}{5}\le\dfrac{x}{8}\le\dfrac{1}{4}\)
\(\Rightarrow\dfrac{-8}{40}\le\dfrac{5x}{40}\le\dfrac{10}{40}\)
\(\Rightarrow5x\in\left\{-5;0;5;10\right\}\)
\(\Rightarrow x\in\left\{-1;0;1;2\right\}\)
e) \(\dfrac{x+46}{20}=x\dfrac{2}{5}\)
\(\Rightarrow\dfrac{x+46}{20}=x+\dfrac{2}{5}\)
\(\Rightarrow\dfrac{x+46}{20}=\dfrac{5x+2}{5}\)
\(\Rightarrow5.\left(x+46\right)=20.\left(5x+2\right)\)
\(\Rightarrow5x+230=100x+40\)
\(\Rightarrow5x-100x=40-230\)
\(\Rightarrow-95x=-190\)
\(\Rightarrow x=-190:-95\)
\(\Rightarrow x=2\)
\(y\dfrac{5}{y}=\dfrac{86}{y}\)
\(\Rightarrow y+\dfrac{5}{y}=\dfrac{86}{y}\)
\(\Rightarrow\dfrac{y^2+5}{y}=\dfrac{86}{y}\)
\(\Rightarrow y^2+5=86\)
\(\Rightarrow y^2=86-5\)
\(\Rightarrow y^2=81\)
\(\Rightarrow\left[{}\begin{matrix}y=9\\y=-9\end{matrix}\right.\)
Chúc bạn học tốt!
x- 280 : 35 = 5.54
x- 8 = 270
x= 278
( x - 128 + 20 ) : 192 = 0
x-128 + 20 = 0
x-128 = -20
x= 180
( x- 280 ) : 35 = 56 : 5
(x- 280) : 35 = 11,2
x-280 = 392
x= 672
460 + 85.4 = ( x + 200 ).4
800 = (x+200) *4
800 : 4 = x+200
200= x + 200
x=0
x : 15 + 42 = 13 + 25.8
x: 15 + 42 = 213
x:15 = 171
x= 2565
x + 5.2 - ( 32 + 16.3 : 16 - 15 ) = 0
x + 10 - 20 =0
x + 10 = 20
x= 10
Bài 2: Đong đầy nước vào can lít.
Đổ lượng nước đó sang can 5 lít cho đến khi đầy can. Số còn lại trong can 7 lít là 2 lít nước.
Làm như trên 1 lần nữa, ta đc 2 lít nước.
Đổ chung 2 lít nước có đc lần 1 và 2 lít nước có đc lần 2 lại vs nhau là đc 4 lít.
(Bài 2 ko chắc chắn lắm đâu)
a) 460 + 85.4 = ( x + 200 ) : 4
=> x = 3000
b) => x = 2595
c) => x = 50
d) => x = 40
a)460 +85 . 4 = (x+200) :4 b)x:15+42=15+25.8
suy ra : 460+340=(x+200):4 suy ra: x:15+42=15+200
suy ra: 800= (x+200):4 suy ra : x:15+42=215
suy ra : 800.4=x+200 suy ra: x:15=215-42
suy ra : 3200=x+200 suy ra : x:15=173
suy ra: x= 3200-200 suy ra : x=173.15
suy ra : x=3000 vậy x =3000 suy ra: x=2595 vậy x = 2595
c) x-32:16=48 d)x-6:2-(48-24.2:6-3)=0
suy ra :x-2=48 suy ra : x-6:2-(48-48:6-3)=0
suy ra :x=48+2 suy ra : x-6:2-(48-8-3)=0
suy ra : x=50 suy ra : x-6:2-(40-3)=0
vậy x=50 suy ra : x-6:2 - 37=0
suy ra : x-3-37=0
suy ra : x-3=0+37
suy ra : x-3=37
suy ra : x=37+3
suy ra :x=40 vậy x= 40
a, 460 + 85 . 4 = ( x + 200 ) : 4
460 + 340 = ( x + 200 ) : 4
( x + 200 ) : 4 = 800
x + 200 = 800 . 4 = 3200
x = 3200 - 200
x = 3000
a) \(5x-65=5.3^2 \\ 5x-65=45\\5x=45+65\\5x=110\\x=22\)
b) \(200-(2x+6)=4^3\\2x+6=200-4^3\\2x+6=136\\2x=130\\x=65\)
c) \(2(x-51)=2.2^3+20\\2(x-51)=16+20\\2(x-51)=36\\x-51=18\\x=51+18=69\)
d) \(135-5(x+4)=35\\5(x+4)=135-45\\5(x-4)=90\\x-4=18\\x=18+4=22\)
e) \((2x-4)(15-3x)=0\\2(x-2).3(5-x)=0\\(x-2)(5-x)=0\\ \left[ \begin{array}{l}x-2=0\\5-x=0\end{array} \right. \\ \left[ \begin{array}{l}x=2\\x=5\end{array} \right.\)
f) \(2^{x+1} . 2^{2014}=2^{2016} \\ (2^{x+1} . 2^{2014}):2^{2014}=2^{2016} :2^{2014} \\ 2^{x=1}=2^{2016-2014} \\2^{x+1}=2^2\\x+1=2\\x=1\)
g) \(15+(x-1)^3=43\\(x-1)^3=15-42\\(x-1)^3=-27\\(x-1)^3=(-3)^3\\x-1=-3\\x=-2\)
h) \(15-x=17+(-9)\\15-x=17-9\\15-x=8\\x=15-8\\x=7\)
i) \(|x-5|=|-7|+|-4|\\|x-5|=7+4\\|x-5|=11\\ \left[ \begin{array}{l}x-5=11\\x-5=-11\end{array} \right. \\ \left[ \begin{array}{l}x=16\\x=-6\end{array} \right.\)
k) \(|x-3|-12=-9+|-7|\\|x-3|-12=-9+7\\|x-3|-12=-2\\|x-3|=10 \\ \left[ \begin{array}{l}x-3=10\\x-3=-10\end{array} \right. \\ \left[ \begin{array}{l}x=13\\x=-7\end{array} \right.\)
460 + 86 . 4 = { x + 200 } . 4
460 + 344 = { x + 200 } : 4
804 = { x + 200 } . 4
x = 200 = 804 : 4
x + 200 = 201
x = 201 - 200
x = 1
a) 460 + 86 . 4 = { x + 200 } . 4
460 + 344 = { x + 200 } . 4
804 = { x + 200 } . 4
x + 200 = 804 : 4
x + 200 = 201
x = 1
b) { x - 128 + 20 } : 192 = 0
{ x - 148 } = 0 . 192
x - 148 = 0
x = 148
c) 3x- 8064 + x = 0
4x - 8064 = 0
4x = 8064
x = 2016
d) ( x + 1 ) ( 3 - x ) ( 2x + 8 ) = 0
\(\Rightarrow\hept{\begin{cases}x+1=0\\3-x=0\\2x+8=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=0-1\\x=3-0\\2x=-8\end{cases}}\Rightarrow\hept{\begin{cases}x=-1\\x=3\\x=-4\end{cases}}\)
e) 25 + ( 15 . x ) = 30
15 . x = 5
x = 5 : 15
x = 5/15 = 1/3