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nhớ giúp nhaaaaa
a, 4x -15=-75-x b,72-3x= 5x+8
4x+x=-75+15 -3x-5x=8-72
5x=-60 -8x=-64
x=-60:5 8x=64
x=-14 x=64:8
x=8
c,3Ix-7I=21 d,-7Ix+3I=-49
Ix-7I=21:3 Ix+3I=-49:-7
Ix-7I=7 Ix+3I=7
x-7=7 hoặc x-7=-7 x+3=7 hoặc x+3=-7
x=14 hoặc x=0 x=4 hoặc x=-10
b) (3.x - 24) . 73 = 2 . 74
(3.x - 24) . 343 = 4802
3.x - 24 = 4802 : 343
3.x - 24 = 14
3.x = 14 + 24
3.x = 38
Tự giải :))
c) x = 1
123 - 5(x + 4) = 38
=> 5(x + 4) = 85
=> x + 4 = 17
=> x = 13
vậy_
(3x - 24).73 = 2.7
=> (3x - 24).73 = 14
=> 3x - 24 = 1022
=> 3x = 1046
=> x = 1046/3
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!
a, 123 - 5 ( x + 4 ) = 38
=> 5(x+4)=123-38
=> 5(x+4)=85
=> x+4=85:5
=>x+4=17
=>x=17-4
=>x=13
b, ( 3x - 24 ) . 73 = 2 . 74
=> (3x-16).343=4802
=> 3x-16=4802:343
=>3x-16=14
=>3x=14+16
=>3x=30
=>x=30:3
=>x=10
c, 5x+3 - 13 = 112
=> 5x+3=112+13
=>5x+3=125
=> 5x+3=53
=> x+3=3
=>x=3-3
=>x=0
a,x=13
b,x=10
c,x=0