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a) x- 25%x= 1/2<=>x-1/4x=1/2<=>3/4x=1/2<=>x=1/2:3/4=2/3
b)\(\left(50\%x+2\frac{1}{4}\right).\frac{-2}{3}=\frac{17}{6}\Leftrightarrow-\frac{1}{3}x-\frac{3}{2}=\frac{17}{6}\Leftrightarrow x=-13\)
c)\(\left(3\frac{x}{7}+1\right):\left(-4\right)=\frac{-1}{28}\Leftrightarrow\frac{28+x}{7}:\left(-4\right)=\frac{-1}{28}\Leftrightarrow\frac{28+x}{-28}=\frac{1}{-28}\Leftrightarrow28+x=1\Leftrightarrow x=-27\)
d)\(\left(1\frac{1}{3}-25\%-\frac{5}{12}\right)-2x=1,6:\frac{3}{5}\Leftrightarrow\frac{2}{3}-2x=\frac{8}{3}\Leftrightarrow x=-1\)
a)x-25%x=1/2
x-1/4x=1/2
x.(1-1/4)=1/2
x.3/4=1/2
x=1/2:3/4
x=2/3
a, 28+2x=35-(-13)
=> 2x=35+13-28
=>2x=20
=> x=10. vậy x=10
chúc bn hok tốt k cho mik nha
a, 2.x + 7 = 15
2x = 8
x = 4
b, 25 – 3.(6 – x) = 22
3.(6-x) = 3
6-x = 1
x = 5
c, [(2x – 11) : 3 + 1].5 = 20
(2x-11) : 3+1 = 4
(2x-11):3 = 3
2x-11 = 1
2x = 12
x = 6
e, 2 . 3x = 10 . 312 + 8 . 274
6x = 3120 + 2192
6x = 5312
x = 5312/6
g, x – 12 = (–8) + (–17)
x - 12 = -25
x = -13
Lần sau tách nhỏ nội dung câu hỏi ra nha em, chứ trả lời thế này biếng lắm '^^ Chị làm chỉ mang tính tham khảo kết quả thôi, còn cụ thể thì em tách từng bước một ra he :>
a, \(2\cdot x+7=15\)
\(\Leftrightarrow2\cdot x=8\)
\(\Leftrightarrow x=4\)
Vậy x = 4.
b, \(25-3\cdot\left(6-x\right)=22\)
\(\Leftrightarrow3\cdot\left(6-x\right)=3\)
\(\Leftrightarrow6-x=1\)
\(\Leftrightarrow x=5\)
Vậy x = 5.
c, \(\left[\left(2x-11\right):3+1\right]\cdot5=20\)
\(\Leftrightarrow\left(2x-11\right):3+1=4\)
\(\Leftrightarrow\left(2x-11\right):3=3\)
\(\Leftrightarrow2x-11=9\)
\(\Leftrightarrow2x=20\)
\(\Leftrightarrow x=10\)
Vậy x = 10.
d, \(\left(25-2x\right)\cdot3:5-32=42\)
\(\Leftrightarrow\)\(\frac{3\cdot\left(25-2x\right)}{5}=74\)
\(\Leftrightarrow3\cdot\left(25-2x\right)=370\)
\(\Leftrightarrow25-2x=\frac{370}{3}\)
\(\Leftrightarrow2x=-\frac{295}{3}\)
\(\Leftrightarrow x\approx49\)
Vậy \(x\approx49\) .
e, \(2\cdot3x=10\cdot312+8\cdot274\)
\(\Leftrightarrow6x=5312\)
\(\Leftrightarrow x=5312:6\approx885\)
Vậy \(x\approx885\) .
g, \(x-12=\left(-8\right)+\left(-17\right)\)
\(\Leftrightarrow x-12=-25\)
\(\Leftrightarrow x=-25+12=-13\)
Vậy x = -13.
h, \(7-2x=18-3x\)
\(\Leftrightarrow-2x+3x=18-7\)
\(\Leftrightarrow x=11\)
Vậy \(x=11\) .
i, \(3\cdot\left(x+5\right)-x-11=24\)
\(\Leftrightarrow3x+15-x-11=24\)
\(\Leftrightarrow2x=24+11-15\)
\(\Leftrightarrow2x=20\)
\(\Leftrightarrow x=10\)
Vậy \(x=10\) .
Tìm x , biết:
a, ( 2x + 1)2 = 93
b, ( 2x + 1)3 = 1252
c, 252< 5x+3 < 254
d, x15= x
e, ( x - 5)4 = ( x-5)6
A) \(\left(2x+1\right)^2=9^3\)
\(\Rightarrow\left(2x+1\right)^2=9^2\times9\)
\(\Rightarrow2x+1=81\)
\(\Rightarrow2x=81-1\)
\(\Rightarrow2x=80\)
\(\Leftrightarrow x=40\)
B) \(\left(2x+1\right)^3=125^2\)
\(\Rightarrow\left(2x+1\right)^3=5^3\)
\(\Rightarrow2x+1=5\)
\(\Rightarrow2x=5-1\)
\(\Leftrightarrow x=2\)
C) \(25^2< 5^{x+3}< 25^4\)
\(\Leftrightarrow5^4< 5^{x+3}< 5^6\)
\(\Leftrightarrow4< x+3< 6\)
\(\Rightarrow x+3=5\)
\(\Rightarrow x=2\)
D) \(x^{15}=x\)
Nếu \(x>1\)thì \(x^{15}>x\)
Vậy \(x=1\)
E) \(\left(x-5\right)^4=\left(x-5\right)^6\)
\(\Rightarrow\left(x-5\right)^4-\left(x-5\right)^6=0\)
\(\Rightarrow\left(x-5\right)\times\left(1^4-1^6\right)=0\)
\(\Rightarrow x-5=0\)
\(\Leftrightarrow x=5\)
KÍCH MK NHA BẠN
a)\(\frac{x}{150}\)=\(\frac{5}{6}\).\(\frac{-7}{25}\)
⇒\(\frac{x}{150}\)=\(\frac{-7}{30}\)
⇒30x=-7.150
⇒x=\(\frac{-1050}{30}\)=-35
vậy x=-35
b)\(\frac{1}{2}\).x+\(\frac{3}{5}.x\)\(=3\)
⇒\(\frac{11}{10}x=3\)
\(\Rightarrow x=\frac{30}{11}\)
Vậy x=\(\frac{30}{11}\)
c)\(25\%.x+x=2\frac{1}{2}\)
\(\Rightarrow\frac{1}{4}.x+x=\frac{5}{2}\)
⇒\(\frac{5}{4}x=\frac{5}{2}\)
⇒\(x=2\)
Vậy\(x=2\)
d)\(\left|2x\right|=15\)
\(\Rightarrow\left[{}\begin{matrix}2x=15\\2x=-15\end{matrix}\right.\)
⇒\(\left[{}\begin{matrix}x=\frac{15}{2}\\x=-\frac{15}{2}\end{matrix}\right.\)
Vậy \(x=\frac{15}{2}\)hoặc \(x=\frac{-15}{2}\)
//học tốt//