TÌm X
(4.X+5):3-121:11=4 12)2x+2x+3=144
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1: =>(4x+5):3-11=41
=>(4x+5):3=52
=>4x+5=156
=>4x=151
hay x=151/4
2: \(\Leftrightarrow2^x\cdot\left(2^3+1\right)=144\)
\(\Leftrightarrow2^x=16\)
hay x=4
a) \(\left(4x+5\right):3-121:11=4\)
\(\Leftrightarrow\left(\dfrac{4x}{3}+\dfrac{5}{3}\right)-11=4\)
\(\Leftrightarrow\dfrac{4x}{3}+\dfrac{5}{3}-11=4\)
\(\Leftrightarrow\dfrac{4x}{3}+\dfrac{5}{3}-\dfrac{33}{3}=4\)
\(\Leftrightarrow\dfrac{4x}{3}+\dfrac{5-33}{3}=4\)
\(\Leftrightarrow\dfrac{4x}{3}-\dfrac{28}{3}=4\)
\(\Leftrightarrow\dfrac{4x}{3}=4+\dfrac{28}{3}\)
\(\Leftrightarrow\dfrac{4x}{3}=\dfrac{12}{3}+\dfrac{28}{3}\)
\(\Leftrightarrow\dfrac{4x}{3}=\dfrac{12+28}{3}\)
\(\Leftrightarrow\dfrac{4x}{3}=\dfrac{40}{3}\)
\(\Leftrightarrow4x=\dfrac{40}{3}.3\)
\(\Leftrightarrow4x=40\)
\(\Leftrightarrow x=\dfrac{40}{4}=10\)
Vậy \(x=10\)
c) ( 2x + 1 )3 =125
=> (2x+1)3=53
=> 2x+1=5
=> 2x=4
=> x=2
vậy x=2
a, 11/12 - ( 2/5 + x ) = 2/3
<=> \(\frac{2}{5}+x=\frac{11}{12}-\frac{2}{3}=\frac{1}{4}\)
=> x=\(\frac{1}{4}-\frac{11}{12}=-\frac{2}{3}\)
b, 2x . ( x - 1/7 ) = 0
<=>\(\left[\begin{array}{nghiempt}x=0\\x-\frac{1}{7}=0\end{array}\right.\)<=> \(\left[\begin{array}{nghiempt}x=0\\x=\frac{1}{7}\end{array}\right.\)
vậy x={\(0;\frac{1}{7}\)}
c, 3/4 + 1/4 : x = 2/5
<=>\(\frac{1}{4}:x=\frac{2}{5}-\frac{3}{4}=-\frac{7}{20}\)
<=> \(x=\frac{1}{4}:\left(-\frac{7}{20}\right)=-\frac{5}{7}\)
vậy x=-5/7
a) \(\frac{11}{12}-\left(\frac{2}{5}+x\right)=\frac{2}{3}\)
\(\Leftrightarrow\frac{11}{12}-\frac{2}{5}-x=\frac{2}{3}\)
\(\Leftrightarrow-x=\frac{2}{3}-\frac{11}{12}+\frac{2}{5}=\frac{3}{20}\)
\(\Leftrightarrow x=-\frac{3}{20}\)
b) \(2x\left(x-\frac{1}{7}\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=0\\x-\frac{1}{7}=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=0\\x=\frac{1}{7}\end{array}\right.\)
c) \(\frac{3}{4}+\frac{1}{4}:x=\frac{2}{5}\)
\(\Leftrightarrow\frac{1}{4x}=\frac{2}{5}-\frac{3}{4}=-\frac{7}{20}\)
\(\Leftrightarrow4x=\frac{-20}{7}\)
\(\Leftrightarrow x=-\frac{5}{7}\)
1) \(\frac{25}{12}.x+\frac{11}{15}=\frac{9}{10}\)
=> \(\frac{25}{12}.x=\frac{9}{10}-\frac{11}{15}\)
=> \(\frac{25}{12}.x=\frac{1}{6}\)
=> \(x=\frac{1}{6}:\frac{25}{12}\)
=> \(x=\frac{2}{25}\)
Vậy \(x=\frac{2}{25}\).
3) \(\frac{29}{12}.\left[x\right]-\frac{5}{6}=\frac{3}{8}\)
=> \(\frac{29}{12}.\left[x\right]=\frac{3}{8}+\frac{5}{6}\)
=> \(\frac{29}{12}.x=\frac{29}{24}\)
=> \(x=\frac{29}{24}:\frac{29}{12}\)
=> \(x=\frac{1}{2}\)
Vậy \(x=\frac{1}{2}\).
4) \(\left[4x+\frac{3}{4}\right]-\frac{5}{4}=2\)
=> \(\left[4x+\frac{3}{4}\right]=2+\frac{5}{4}\)
=> \(4x+\frac{3}{4}=\frac{13}{4}\)
=> \(4x=\frac{13}{4}-\frac{3}{4}\)
=> \(4x=\frac{5}{2}\)
=> \(x=\frac{5}{2}:4\)
=> \(x=\frac{5}{8}\)
Vậy \(x=\frac{5}{8}\).
5) 2x + 2x+3 = 144
⇔ 2x + 2x . 23 = 144
⇔ 2x . (1 + 23) = 144
⇔ 2x . 9 = 144
⇔ 2x = 144 : 9
⇔ 2x = 16
⇔ 2x = 24
=> x = 4
Vậy x = 4.
Chúc bạn học tốt!
(4x+5) : 3 -121 : 11 = 4
=> (4x + 5) : 3 - 11 = 4
=> (4x + 5) : 3 = 15
=> 4x + 5= 45
=> 4x = 40
=> x=10
Vậy...
(2x + 1)3 = 125
=> (2x + 1)3= 53
=> 2x + 1= 5
=> 2x= 4
=> x=2
Vậy...
(4x - 1)2 = 25.9
=> (4x - 1)2= (5.3)2
=> 4x - 1= 15
=> 4x = 16
=> x = 4
Vậy...
2x + 2x+3= 144
=> 2x . (1 + 23) = 144
=> 2x . 9= 144
=> 2x = 16 = 24
=> x= 4
Vậy...
1 + 3 + 5 + ... + x = 1000 ( x lẻ)
Số số hạng của dãy số (1 + 3 + 5 + ... + x) là:
(x - 1) : 2 + 1 = (x-1)/2 + 2/2 = x - 1 + 2= (x + 1)/2 (số hạng)
=> (x+1)(x+1)/2 : 2=1000
=> (x+1)(x+1)=4000
=> (x+1)2= 4000
Ta có: 4000= 25.53
=> 4000 có số lượng ước là: (5+1).(3+1)= 24 là số chẵn
=> 4000 k phải là số chính phương
=> Không tìm được giá trị của x
Vậy...
a)(4.X+5):3-121:11=4
\(\Leftrightarrow\left(4x+5\right):3-11=4\)
\(\Leftrightarrow\left(4x+5\right):3=15\)
\(\Leftrightarrow4x+5=45\)
\(\Leftrightarrow4x=40\)
\(\Leftrightarrow x=10\)
b)2x+2x+3=144
\(\Leftrightarrow2^x\left(1+2^3\right)=144\)
\(\Leftrightarrow2^x=16\)
\(\Leftrightarrow2^x=2^4\)
\(\Leftrightarrow x=4\)
lần sau viết đề cho hẳn hoi