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1,a,\(\left|x+2\right|=x+3\Leftrightarrow\orbr{\begin{cases}x+2=x+3\\x+2=-x-3\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x-x=3-2\\x+x=-3-2\end{cases}\Leftrightarrow\orbr{\begin{cases}0=1\left(voly\right)\\x=\frac{-5}{2}\end{cases}}}\)
b, \(|x-2|=2-x\Leftrightarrow\orbr{\begin{cases}x-2=2-x\\x-2=x-2\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x+x=2+2\\x-x=-2+2\end{cases}\Rightarrow x=2}\)
c,\(\left|2x-1\right|=3\Leftrightarrow\orbr{\begin{cases}2x-1=3\\2x-1=-3\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}2x=4\\2x=-2\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2\\x=-1\end{cases}}}\)
d,\(\left|x-12\right|=x\Leftrightarrow\orbr{\begin{cases}x-12=x\\x-12=-x\end{cases}\Leftrightarrow\orbr{\begin{cases}0=12\left(voly\right)\\x=6\end{cases}}}\)
a: \(4x^3+12=120\)
=>\(4x^3=108\)
=>\(x^3=27=3^3\)
=>x=3
b: \(\left(x-4\right)^2=64\)
=>\(\left[{}\begin{matrix}x-4=8\\x-4=-8\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=12\\x=-4\end{matrix}\right.\)
c: (x+1)^3-2=5^2
=>\(\left(x+1\right)^3=25+2=27\)
=>x+1=3
=>x=2
d: 136-(x+5)^2=100
=>(x+5)^2=36
=>\(\left[{}\begin{matrix}x+5=6\\x+5=-6\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=1\\x=-11\end{matrix}\right.\)
e: \(4^x=16\)
=>\(4^x=4^2\)
=>x=2
f: \(7^x\cdot3-147=0\)
=>\(3\cdot7^x=147\)
=>\(7^x=49\)
=>x=2
g: \(2^{x+3}-15=17\)
=>\(2^{x+3}=32\)
=>x+3=5
=>x=2
h: \(5^{2x-4}\cdot4=10^2\)
=>\(5^{2x-4}=\dfrac{100}{4}=25\)
=>2x-4=2
=>2x=6
=>x=3
i: (32-4x)(7-x)=0
=>(4x-32)(x-7)=0
=>4(x-8)*(x-7)=0
=>(x-8)(x-7)=0
=>\(\left[{}\begin{matrix}x-8=0\\x-7=0\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=8\\x=7\end{matrix}\right.\)
k: (8-x)(10-2x)=0
=>(x-8)(x-5)=0
=>\(\left[{}\begin{matrix}x-8=0\\x-5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=8\\x=5\end{matrix}\right.\)
m: \(3^x+3^{x+1}=108\)
=>\(3^x+3^x\cdot3=108\)
=>\(4\cdot3^x=108\)
=>\(3^x=27\)
=>x=3
n: \(5^{x+2}+5^{x+1}=750\)
=>\(5^x\cdot25+5^x\cdot5=750\)
=>\(5^x\cdot30=750\)
=>\(5^x=25\)
=>x=2
\(6.\left(x-5\right)-12\left(x-3\right)-7\left(2-x\right)=-108\)
\(\Leftrightarrow6x-30-12x+36-14+7x=-108\)
\(\Leftrightarrow x=-100\)(Chuyển vế tất cả một bên là x và bên kia là số)
(Tớ chắc chắn là đúng, click cho tớ với nhá!)
Lời giải:
$45-5(x+4)=10$
$5(x+4)=45-10=35$
$x+4=35:5=7$
$x=7-4=3$
------------------------
$(7x-15):3-6=17$
$(7x-15):3=17+6=23$
$7x-15=23\times 3=69$
$7x=69+15=84$
$x=84:7=12$
------------------
$3^{x+2}-5.3^x=108$
$3^x(3^2-5)=108$
$3^x.4=108$
$3^x=108:4=27=3^3$
$\Rightarrow x=3$
\(45-5\left(x+4\right)=10\)
\(\Rightarrow5\left(x+4\right)=45-10\)
\(\Rightarrow5\left(x+4\right)=35\)
\(\Rightarrow x+4=35:5\)
\(\Rightarrow x+4=7\)
\(\Rightarrow x=7-4\)
\(\Rightarrow x=3\)
______________
\(\left(7x-15\right):3-6=17\)
\(\Rightarrow\left(7x-15\right):3=17+6\)
\(\Rightarrow\left(7x-15\right):3=23\)
\(\Rightarrow7x-15=23\cdot3\)
\(\Rightarrow7x-15=69\)
\(\Rightarrow7x=69+15\)
\(\Rightarrow7x=84\)
\(\Rightarrow x=12\)
______________
\(3^{x+2}-5\cdot3^x=108\)
\(\Rightarrow3^x\cdot\left(3^2-5\right)=108\)
\(\Rightarrow3^x\cdot\left(9-5\right)=108\)
\(\Rightarrow3^x\cdot4=108\)
\(\Rightarrow3^x=108:4\)
\(\Rightarrow3^x=27\)
\(\Rightarrow3^x=3^3\)
\(\Rightarrow x=3\)
Bài làm
a) 11 - 12 + 13 - 14 + 15 - 16 + 17 - 18 + 19 - 20
= ( 11 - 12 ) + ( 13 - 14 ) + ( 15 - 16 ) + ( 17 - 18 ) + ( 19 - 20 )
= ( -1 ) + ( -1 ) + ( -1 ) + ( -1 ) + ( -1 )
= -5
b) 101 - 102 - ( - 103 ) - 104 - ( - 105 ) - 106 - ( - 107 ) - 108 - ( - 109 ) - 110
= 101 - 102 + 103 - 104 + 105 - 106 + 107 - 108 + 109 - 110
= ( 101 - 102 ) + ( 103 - 104 ) + ( 105 - 106 ) + ( 107 - 108 ) + ( 109 - 110 )
= ( -1 ) + ( -1 ) + ( -1 ) + ( -1 ) + ( -1 )
= -5
# Học tốt #
a)11 - 12 + 13 - 14 + 15 - 16 + 17 - 18 + 19 - 20
= (11 - 12) + (13 - 14) + (15 - 16) + (17 - 18) + ( 19 - 20)
= (-1) + (-1) + (-1) + (-1) + (-1) = (-1) . 5 = - 5
b)101-102-(-103)-104-(-105)-106-(-107)-108-(-109)-110
= 101-102+103-104+105-106+107-108+109-110
= (101-102)+(103-104)+(105-106)+(107-108)+(109-110)
= (-1) + (-1) + (-1) + (-1) + (-1)
= (-1) . 5
= -5
a,11-12+13-14+15-16+17-18+19-20
=(11-12)+(13-14)+(15-16)+(17-18)+(19-20)
=(-1)+(-1)+(-1)+(-1)+(-1)
=-5
b,101-102-(-103)-104-(-105)-106-(-107)-108-(-109)-110
=101-102+103-104+105-106+107-108+109-110
=(101-102)+(103-104)+(105-106)+(107-108)+(109-110)
=(-1)+(-1)+(-1)+(-1)+(-1)
=-5
\(a,12^{13}.18^9.24^{25}\)
\(=2^{26}.3^{13}.2^9.3^{18}.2^{50}.3^{25}\)
\(=2^{85}.3^{56}\)
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a)\(12-\left[25+\left(6+3\right)^2\right]\)
\(=12-\left[25+9^2\right]\)
\(=12-\left[25+81\right]\)
\(=12-106\)
\(=\left(-94\right)\)
b) \(315-\left(8^6\div8^4-12.3+7+7^3\right)\)
\(=316-\left(8^2-36+7+343\right)\)
\(=316-\left(64-43+343\right)\)
\(=316-\left(21+343\right)\)
\(=316-364\)
\(=\left(-48\right)\)
17-2x=108:12
17-2x=9
2x=17-9
2x=8
x=8:2
x=4
\(17-2x=108:12\)
\(17-2x=9\)
\(2x=26\)
\(x=13\)
Vậy \(x=13\)