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320 : ( x - 1 ) = ( 53 - 52 ) : 4 + 15
<=> 320 : ( x - 1 ) = ( 125 - 25 ) : 4 + 15
<=> 320 : ( x - 1 ) = 100 : 4 + 15
<=> 320 : ( x - 1 ) = 40
<=> x - 1 = 8
<=> x = 9
240 : ( x - 5 ) = 22 . 52 - 20
<=> 240 : ( x - 5 ) = 4 . 25 - 20
<=> 240 : ( x - 5 ) = 80
<=> x - 5 = 3
<=> x = 8
70 : ( x - 3 ) = ( 34 - 1 ) : 4 - 16
<=> 70 : ( x - 3 ) = 80 : 4 - 16
<=> 70 : ( x - 3 ) = 4
<=> x - 3 = 35/2
<=> x = 41/2
a) 320: (x-1) = (53 - 52):4 + 15 b) 240: (x-5) = 22.52 - 20 c) 70:(x-3) = (34 - 1):4 - 16
320: (x-1) = (125- 25): 4 + 15 240: (x-5) = 4.25 - 20 70:(x-3) = (81-1): 4 - 16
320: (x-1) = 100:4 + 15 240: (x-5) = 100 - 20 70: (x-3) = 80: 4 - 16
320: (x-1) = 25 + 15 240: (x-5) = 80 70: (x-3) = 20 -16
320: (x-1) = 40 (x-5) = 240:80 70: (x-3) = 4
(x-1) = 320:40 (x-5) = 3 (x-3) = 70:4
(x-1) = 80 x = 5+3 (x-3) = 17,5
x = 80+1 x = 8 x = 17,5 : 3
x = 81 x = 5,83
\(a)\frac{2}{3}x-\frac{1}{2}=\frac{5}{12}\)
\(\Rightarrow\frac{2}{3}x=\frac{5}{12}+\frac{1}{2}=\frac{11}{12}\)
\(\Rightarrow x=\frac{11}{12}:\frac{2}{3}=\frac{11}{8}\)
\(b)\left(2\frac{4}{5}x-50\right):\frac{2}{3}=51\)
\(\Rightarrow\frac{14}{5}x-50=51.\frac{2}{3}=34\)
\(\Rightarrow\frac{14}{5}x=34+50=84\)
\(\Rightarrow x=84:\frac{14}{5}=30\)
a) 2/3.x - 1/2 = 5/12
2/3.x = 5/12 + 1/2
2/3.x = 11/12
x = 11/12 : 2/3
x = 11/8
b) \(\left(2\frac{4}{5}.x-50\right):\frac{2}{3}=51\)
\(\frac{14}{5}.x-50=51.\frac{2}{3}\)
\(\frac{14}{5}.x-50=34\)
\(\frac{14}{5}.x=34+50\)
\(\frac{14}{5}.x=84\)
\(x=84:\frac{14}{5}\)
\(x=30\)
các bạn ơi mình đang cần gấp . Mình chỉ còn 20 phút thui . HUHU
Bài làm :
1) \(\frac{x+11}{4}=\frac{2x+4}{5}\)
\(\Leftrightarrow\left(x+11\right).5=4.\left(2x+4\right)\)
\(\Leftrightarrow5x+55=8x+16\)
\(\Leftrightarrow5x-8x=16-55\)
\(\Leftrightarrow-3x=-39\)
\(\Leftrightarrow x=\frac{-39}{-3}=\frac{39}{3}=13\)
2)\(\frac{x+4}{x+10}=\frac{3}{5}\)
\(\Leftrightarrow\left(x+4\right).5=\left(x+10\right).3\)
\(\Leftrightarrow5x+20=3x+30\)
\(\Leftrightarrow5x-3x=30-20\)
\(\Leftrightarrow2x=10\)
\(\Leftrightarrow x=\frac{10}{2}=5\)
3)\(\frac{x+8}{x+14}=\frac{2}{3}\)
\(\Leftrightarrow\left(x+8\right).3=\left(x+14\right).2\)
\(\Leftrightarrow3x+24=2x+28\)
\(\Leftrightarrow3x-2x=28-24\)
\(\Leftrightarrow x=4\)
\(\frac{x+3}{15}=\frac{1}{3}\)
\(\Rightarrow x+3=\frac{1}{3}\cdot15\)
\(\Rightarrow x=5-3\)
\(\Rightarrow x=2\)
\(\frac{x+3}{15}=\frac{1}{3}\)
\(x+3=\frac{1}{3}\times15\)
x+3=5
x=5-3
x=2
a) \(3\left(4-2x\right)-2\left(x+3\right)=12-7x\)
\(\Leftrightarrow\)\(12-6x-2x-6=12-7x\)
\(\Leftrightarrow\)\(6-8x=12-7x\)
\(\Leftrightarrow\)\(x=-6\)
Vậy...
b) \(\left|16+\right|3\left(x-2\right)||-5=20\)
\(\Leftrightarrow\)\(\left|16+\right|3\left(x-2\right)||=25\)(1)
Ta thấy: \(\left|3\left(x-2\right)\right|\ge0\)\(\Rightarrow\)\(16+\left|3\left(x-2\right)\right|>0\)
nên từ (1) \(\Rightarrow\) \(16+\left|3\left(x-2\right)\right|=25\)
\(\Leftrightarrow\)\(\left|3\left(x-2\right)\right|=9\)
\(\Leftrightarrow\) \(\orbr{\begin{cases}3\left(x-2\right)=9\\3\left(x-2\right)=-9\end{cases}}\)
\(\Leftrightarrow\) \(\orbr{\begin{cases}x-2=3\\x-2=-3\end{cases}}\)\(\Leftrightarrow\)\(\orbr{\begin{cases}x=5\\x=-1\end{cases}}\)
Vậy....
c) \(\left|-5-3^2\right|-||3x+5|-7.2^3|=3^9:3^7\)
\(\Leftrightarrow\)\(14-||3x+5|-56|=9\)
\(\Leftrightarrow\)\(||3x+5|-56|=5\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}\left|3x+5\right|-56=5\\\left|3x+5\right|-56=-5\end{cases}}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}\left|3x+5\right|=61\\\left|3x+5\right|=51\end{cases}}\)
đến đây bn giải tiếp nhé
\(2^{x+3}.4^2=64\Leftrightarrow2^{x+3}.2^4=64\Leftrightarrow2^{x+7}=2^6\Leftrightarrow x+7=6\Leftrightarrow x=-1\)
a,ĐK : x \(\ne\)3/7
\(\frac{24}{7x-3}=-\frac{4}{25}\Leftrightarrow600=-28x+12\Leftrightarrow-28x=588\Leftrightarrow x=-21\)
b, ĐK : x;y \(\ne\)6
Xét : \(\frac{4}{x-6}=-\frac{12}{18}\Leftrightarrow72=-12x+72\Leftrightarrow x=0\)
Xét : \(\frac{y}{24}=-\frac{12}{18}\Leftrightarrow18y=-288\Leftrightarrow y=-16\)
\(\frac{24}{7.x-3}=-\frac{4}{25}\)
24.25=7.x-3.-4
600=7.x-3.-4
7.x-3.-4=600
7.x-3=600:-4
7.x-3=-150
7.x=-150+3
7.x=-147
x=-147:7
x=-21
vậy x=-21
\(\Rightarrow\frac{2x}{4}-\frac{3}{5}=\frac{x}{4}\)
\(\Rightarrow\frac{2x}{4}-\frac{x}{4}=\frac{3}{5}\)
\(\Rightarrow\frac{x}{4}=\frac{3}{5}\)
=> 5x = 12
=> x= 12/5
a, \(\left(x-\frac{2}{3}\right)^2=\frac{5}{6}\Leftrightarrow\orbr{\begin{cases}x-\frac{2}{3}=\sqrt{\frac{5}{6}}\\x-\frac{2}{3}=-\sqrt{\frac{5}{6}}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{4+\sqrt{30}}{6}\\x=\frac{4-\sqrt{30}}{6}\end{cases}}}\)nghiệm xấu thế ?
b, \(\left(\frac{3}{4}-x\right)^3=\left(-8\right)\Leftrightarrow\frac{3}{4}-x=-2\Leftrightarrow x=\frac{11}{4}\)
<=> |x+2| = 13
<=> \(\orbr{\begin{cases}x+2=13\\x+2=-13\end{cases}\Rightarrow}\orbr{\begin{cases}x=11\\x=-15\end{cases}}\)
Vậy.........
hok tốt
..........
\(|x+2|=12+\left(-3\right)+\left|-4\right|\)
\(|x+2|=12-3+4\)
\(\left|x+2\right|=13\)
\(\Rightarrow x\in\left\{-15;11\right\}\)
x/x = 12/1 +5/1
x/x = 3/4 - 17/1
x/x = -65/4