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a) \(\left(7x-11\right)^3=2^5.5^2+200\)
\(\Rightarrow\left(7x-11\right)^3=32.25+200\)
\(\Rightarrow\left(7x-11\right)^3=800+200\)
\(\Rightarrow\left(7x-11\right)^3=1000\)
\(\Rightarrow\left(7x-11\right)^3=10^3\)
\(\Rightarrow7x-11=10\)
\(\Rightarrow7x=10+11\)
\(\Rightarrow7x=21\)
\(\Rightarrow x=21:7\)
\(\Rightarrow x=3\)
Vậy x = 3
b) \(\left(2x-15\right)^5=\left(2x-15\right)^3\)
\(\Rightarrow\left(2x-15\right)^5-\left(2x-15\right)^3=0\)
\(\Rightarrow\left(2x-15\right)^3\left[\left(2x-15\right)^2-1\right]=0\)
\(\Rightarrow\orbr{\begin{cases}\left(2x-15\right)^3=0\\\left(2x-15\right)^2-1=0\end{cases}}\Rightarrow\orbr{\begin{cases}\left(2x-15\right)^3=0\\\left(2x-15\right)^2=1\end{cases}}\)
TH 1 : \(\left(2x-15\right)^3=0\Rightarrow2x-15=0\Rightarrow2x=15\Rightarrow x=\frac{15}{2}\)
TH 2 : \(\left(2x-15\right)^2=1\Rightarrow\orbr{\begin{cases}2x-15=1\\2x-15=-1\end{cases}}\Rightarrow\orbr{\begin{cases}2x=16\\2x=14\end{cases}}\Rightarrow\orbr{\begin{cases}x=8\\x=7\end{cases}}\)
Vậy \(x\in\left\{\frac{15}{2};8;7\right\}\)
_Chúc bạn học tốt_
Bài 1:
a) (2^9 . 3 + 2^9 . 5) : 2^12
= [2^9 . (3 + 5)] : 2^12
= [2^9 . 8] : 2^12
= [2^9 . 2^3] : 2^12
= 2^12 : 2^12
= 1
b) 13^2 - (5^2 . 4 + 2^2 . 15)
= 13^2 - (5^2 . 4 + 4 . 15)
= 13^2 - [4 . (5^2 + 15)]
= 13^2 - [4 . (25 + 15)]
= 13^2 - [4 . 40]
= 13^2 - 160
= 13^2 - 40^2
= -27^2
= 729
Bài 2:
a) 30 . (2^2 . 15 - x) = 30
2^2 . 15 - x = 30 : 30
2^2 . 15 - x = 1
4 . 15 = 1 + x
60 = 1 + x
=> x = 60 - 1
x = 59
Bài 2:
b) 2^4 . 38 - 2^4 . x = 16
16 . (38 - x) = 16
38 - x = 16 : 16
38 - x = 1
x = 38 - 1
x = 37
c) (7 . x - 11^3) = 2^5 . 5^2 + 200
(7 . x - 11^3) = 2^5 . 5^2 + 5^2 . 2^3
(7 . x - 11^3) = 5^2 . (2^5 + 2^3)
(7 . x - 11^3) = 25 . 40
(7 . x - 1331) = 1000
7 . x = 1000 + 1331
7 . x = 2331
x = 2331 : 7
x = 333.
a) (x-1)2-196=0
(x-1)2 =196
x-1 =\(\pm\)14
nẾU X-1= 14 \(\Rightarrow X=15\)
nẾU X-1=-14\(\Rightarrow X=-13\)
Vậy \(x\in\hept{\begin{cases}\\\end{cases}15;-13}\)
b) 2x -15=17
2x =32
2x =25
Vậy x=5
c)(7x-11)3=25.52 +200
(7x-11)3=1000
(7x-11)3 =103
7x-11 =10
7x =21
Vậy x\(\in\varnothing\)
d) x2 =x
x2 -x =0
x(x-1) =0
\(\Rightarrow\)x=0 hoặc x-1 =0
......................................
e) x3 =x
x3 -x =0
x2 (x-1)=0
\(\Rightarrow\)x2=0 hoặc x-1 =0
Nếu x2 =0 \(\Rightarrow\)x=0
........................................
a) (7x - 11)3 = 25.52 + 200
=> (7x - 11)3 = 1000
=> (7x - 11)3 = 103
=> 7x - 11 = 10
=> 7x = 10 + 11
=> 7x = 21
=> x = 21 : 7
=> x = 3
b) x10 = 1x
=> x10 = 1
=> x10 = 110
=> x = 1
c) x10 = x
=> x10 - x = 0
=> x(x9 - 1) = 0
=> \(\orbr{\begin{cases}x=0\\x^9-1=0\end{cases}}\)
=> \(\orbr{\begin{cases}x=0\\x^9=1\end{cases}}\)
=> \(\orbr{\begin{cases}x=0\\x=1\end{cases}}\)
Vậy...
a) 2x-15=17
2x = 17+15 = 32
x = 32 : 2 =16
b) \(2^x.4=128\)
\(2^x=128:4=32\)
Mà \(32=2^5\)
Vậy x = 5