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a) ! x ! + 23 = 45
! x ! = 45 - 23
! x ! = 22
-> x = 22 hoặc x = -22
b) ! x + 2 ! - 32 = 34
! x + 2 ! = 34 + 32
! x + 2 ! = 66
-> x + 2 = 66 hoặc x + 2 = -66
Nếu x + 2 = 66 thì Nếu x + 2 = -66
x = 66 - 2 = 64 x = -66 - 2 = -68
c) 234 + ( 34 - 23 ) + x = 546
234 + 11 + x = 546
245 + x = 546
x = 546 - 245
x = 301
a) \(\left|x\right|+23=45\)
\(\left|x\right|=45-23\)
\(\left|x\right|=22\)
\(\Rightarrow\orbr{\begin{cases}x=22\\x=-22\end{cases}}\)
vậy \(\orbr{\begin{cases}x=22\\x=-22\end{cases}}\)
b) \(\left|x+2\right|-32=34\)
\(\left|x+2\right|=34+32\)
\(\left|x+2\right|=66\)
\(\Rightarrow\orbr{\begin{cases}x+2=66\\x+2=-66\end{cases}}\Rightarrow\orbr{\begin{cases}x=64\\x=-68\end{cases}}\)
vậy \(\orbr{\begin{cases}x=64\\x=-68\end{cases}}\)
c) \(234+\left(34-23\right)+x=546\)
\(11+x=546-234\)
\(x=312-11\)
\(x=301\)
vậy \(x=301\)
a) 3.
b) 1.
c ) 1 2 + − 2 3 + 1 6 + 3 7 = 3 6 + − 4 6 + 1 6 + 3 7 = 3 7 ; d ) 1 2 + 2 8 + 3 4 + 4 5 + 5 6 = 30 60 + 40 60 + 45 60 + 48 60 + 50 60 = 71 5
\(\left(1^2+2^3+3^4+4^5\right)\left(1^3+2^3+3^3+4^3\right)\left(3^8-81^2\right)\\ =\left(1^2+2^3+3^4+4^5\right)\left(1^3+2^3+3^3+4^3\right)\left[3^8-\left(3^4\right)^2\right]\\ =\left(1^2+2^3+3^4+4^5\right)\left(1^3+2^3+3^3+4^3\right)\left(3^8-3^8\right)\\ =\left(1^2+2^3+3^4+4^5\right)\left(1^3+2^3+3^3+4^3\right).0=0\)
\(\left(1^2+2^3+3^4+4^5\right)\left(1^3+2^3+3^3+4^3\right)\left(3^8-81^2\right)=\left(1^2+2^3+3^4+4^5\right)\left(1^3+2^3+3^3+4^3\right)\left(3^8-3^8\right)=\left(1^2+2^3+3^4+4^5\right)\left(1^3+2^3+3^3+4^3\right).0=0\)
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
\(60+x-34=43\Rightarrow x=43+34-60=17\)
\(23x-6.23+69x=230\)
\(\Rightarrow23x+69x=230+6.23\)
\(\Rightarrow92x=368\Rightarrow x=368:92\Rightarrow x=4\)
\(\left(15.24-x\right):0,25=100:0,25\)
\(\Rightarrow\left(360-x\right)=100:0,25.0,25\)
\(\Rightarrow360-x=100\Rightarrow x=360-100=260\)
\(\left(7x+8\right):5=10\Rightarrow\left(7x+8\right)=10.5\)
\(\Rightarrow7x+8=50\Rightarrow7x=50-8\Rightarrow7x=42\Rightarrow x=42:7=6\)
\(280:\left(7+3x\right)=4\Rightarrow\left(7+3x\right)=280:4\)
\(\Rightarrow7+3x=70\Rightarrow3x=70-7\Rightarrow3x=63\Rightarrow x=63:3=21\)
\(\left(x+5\right)x19:13=57\)
\(\Rightarrow\left(x+5\right)x19=57.13\)
\(\Rightarrow\left(x+5\right)=741:19\Rightarrow x+5=39\Rightarrow x=39-5=34\)
\(4\left(36-4x\right)=64\)
\(\Rightarrow\left(36-4x\right)=64:4\)
\(\Rightarrow36-4x=16\)
\(\Rightarrow4x=36-16\Rightarrow4x=20\Rightarrow x=20:4=5\)
\(\left(7,6:1,9\right)x=3,2\)
\(\Rightarrow4x=3,2\Rightarrow x=3,2:4=0,8\)
\(\left(x:2+50\right):5=12\)
\(\Rightarrow x:2+50=12.5\)
\(\Rightarrow x:2=60-50\Rightarrow x:2=10\Rightarrow x=10.2=20\)
D = 2 3 − 1 2 . 1 4 = 1 24 E = 2 3 − 1 2 . 1 4 = 13 24 F = 3 4 − 1 − 2 . 4 6 − 1 3 = 5 12