a) 3+2x-1 = 24 - [ 42-(22-1) ]
b) (19x+2.52):14 = (13-8)2-42
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Những câu hỏi liên quan
10 tháng 10 2021
\(a,\Rightarrow2^{x-1}=24-\left(16-3\right)-3\\ \Rightarrow2^{x-1}=24-13-3\\ \Rightarrow2^{x-1}=8=2^3\\ \Rightarrow x-1=3\Rightarrow x=4\\ b,\Rightarrow\left(19x+50\right):14=25-16=9\\ \Rightarrow19x+50=126\\ \Rightarrow x=4\)
1
2 tháng 12 2021
\(a,\Rightarrow12x-91=101\\ \Rightarrow12x=192\\ \Rightarrow x=16\\ b,\Rightarrow x:23+45=133\\ \Rightarrow x:23=88\\ \Rightarrow x=\dfrac{88}{23}\\ c,\Rightarrow\left(6x-39\right):7=3\\ \Rightarrow6x-39=21\\ \Rightarrow6x=60\\ \Rightarrow x=10\\ d,\Rightarrow3x-24=\dfrac{148}{73}\\ \Rightarrow3x=\dfrac{1900}{73}\\ \Rightarrow x=\dfrac{1900}{219}\\ e,\Rightarrow\left[{}\begin{matrix}x=0\\x=10\end{matrix}\right.\\ f,\Rightarrow\left[{}\begin{matrix}x=-1\\x=2\end{matrix}\right.\\ d,\left(9-x\right)^3=64=4^3\\ \Rightarrow9-x=4\\ \Rightarrow x=5\\ h,\Rightarrow x=27\\ i,\Rightarrow6x=312\cdot12=624\cdot6\\ \Rightarrow x=624\\ j,\Rightarrow\left(19x+104\right):14=25-42=-17\\ \Rightarrow19x+104=-238\\ \Rightarrow19x=-342\\ \Rightarrow x=-18\)
ND
Nguyễn Đức Trí
VIP
21 tháng 7 2023
\(...\Rightarrow\left(19x+50\right):14=5^2-4\Rightarrow\left(19x+50\right):14=21\Rightarrow\left(19x+50\right)=21.14\)
\(\Rightarrow19x+50=294\Rightarrow19x=244\Rightarrow x=\dfrac{244}{19}\)
CM
2 tháng 5 2019
a, 2.(x – 5)+7 = 77
<=> 2.(x – 5) = 70 <=> x – 5 = 35 <=> x = 40
b, x - 1 3 - 3 5 : 3 4 + 2 . 2 3 = 14
<=> x - 1 3 - 3 + 2 4 = 14
<=> x - 1 3 = 14 + 3 - 16 = 1
<=> x – 1 = 1 <=> x = 2
c, 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 = 2 x - 1 - 1
Đặt: A = 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 => 2A = 2 + 2 2 + 2 3 + . . . + 2 2017
=> 2A – A = ( 2 + 2 2 + 2 3 + . . . + 2 2017 ) – ( 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 )
=> A = 2 2017 - 1
Ta có: 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 = 2 x - 1 - 1 => 2 2017 - 1 = 2 x - 1 - 1 => x = 2018
d, 5 2 x - 3 - 2 . 5 2 = 5 2 . 3
<=> 5 2 x - 3 = 5 2 . 3 + 5 2 . 2
<=> 5 2 x - 3 = 5 2 . ( 3 + 2 )
<=> 5 2 x - 3 = 5 3
<=> 2x – 3 = 3 => x = 3
TT
3
N
3 tháng 10 2021
a, ( 19x + 2.52 ) : 14 = ( 13 - 8 )2 - 42
( 19x + 2.52 ) : 14 = ( 13 - 8 )2 - 16
( 19x + 2.52 ) : 14 = 52 - 16
( 19x + 2.52 ) : 14 = 25 - 16
( 19x + 2.52 ) : 14 = 9
( 19x + 2.25 ) : 14 = 9
( 19x + 2.25 ) = 9 . 14
( 19x + 2.25 ) = 126
( 19x + 50 ) = 126
19x = 126 - 50
19x = 76
x = 76 : 19
x = 4
Vậy x = 4
b, 2 . 3x = 10 . 312 + 8 . 274
2 . 3x = 10 . 274 + 8 . 274
2 . 3x = 274 . ( 10+8 )
2 . 3x = 274 . 18
2 . 3x = 9565938
3x = 9565938 : 2
3x = 4782969
3x = 314
=> x = 14
Vậy x = 14
Đây nha bạn!!!
Chúc bạn học tốt!!!
6 tháng 10 2021
a, ( 19x + 2.52 ) : 14 = ( 13 - 8 )2 - 42
( 19x + 2.52 ) : 14 = ( 13 - 8 )2 - 16
( 19x + 2.52 ) : 14 = 52 - 16
( 19x + 2.52 ) : 14 = 25 - 16
( 19x + 2.52 ) : 14 = 9
( 19x + 2.25 ) : 14 = 9
( 19x + 2.25 ) = 9 . 14
( 19x + 2.25 ) = 126
( 19x + 50 ) = 126
19x = 126 - 50
19x = 76
x = 76 : 19
x = 4
Vậy x = 4
b, 2 . 3x = 10 . 312 + 8 . 274
2 . 3x = 10 . 274 + 8 . 274
2 . 3x = 274 . ( 10+8 )
2 . 3x = 274 . 18
2 . 3x = 9565938
3x = 9565938 : 2
3x = 4782969
3x = 314
=> x = 14
Vậy x = 14
7 tháng 3 2018
1,
a,-3/5
b,-1/2
c,19/39
d,1/4
e,-39/40
f,-59/56
2,
a,=
b,<
c,>
d,<
k cho mình nha
9 tháng 8 2023
a) \(\dfrac{3}{8}+\dfrac{7}{12}+\dfrac{10}{16}+\dfrac{10}{24}\)
\(=\dfrac{3}{8}+\dfrac{7}{12}+\dfrac{5}{8}+\dfrac{5}{12}\)
\(=\left(\dfrac{3}{8}+\dfrac{5}{8}\right)+\left(\dfrac{7}{12}+\dfrac{5}{12}\right)\)
\(=1+1\)
\(=2\)
b) \(\dfrac{4}{6}+\dfrac{7}{13}+\dfrac{17}{9}+\dfrac{19}{13}+\dfrac{1}{9}+\dfrac{14}{6}\)
\(=\dfrac{2}{3}+\dfrac{7}{13}+\dfrac{17}{9}+\dfrac{19}{13}+\dfrac{1}{9}+\dfrac{7}{3}\)
\(=\left(\dfrac{2}{3}+\dfrac{7}{3}\right)+\left(\dfrac{7}{13}+\dfrac{19}{13}\right)+\left(\dfrac{17}{9}+\dfrac{1}{9}\right)\)
\(=3+2+2\)
\(=7\)
c) \(\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}+\dfrac{1}{56}\)
\(=\dfrac{1}{1\cdot2}+\dfrac{1}{2\cdot3}+\dfrac{1}{3\cdot4}+\dfrac{1}{4\cdot5}+\dfrac{1}{5\cdot6}+\dfrac{1}{6\cdot7}\)
\(=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}\)
\(=1-\dfrac{1}{7}\)
\(=\dfrac{6}{7}\)