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\(\dfrac{8^2.125.9^2-32.5^3.81}{20^3.3^4-6^8.5^4}\)
\(=\dfrac{2^6.5^3.3^4-2^5.5^3.3^4}{4^3.5^3.3^4-2^8.3^8.5^4}\)
\(=\dfrac{2^6.5^3.3^4-2^5.5^3.3^4}{2^6.5^3.3^4-2^8.3^8.5^4}\)
\(=\dfrac{2^5.5^3.3^4\left(2-1\right)}{2^6.5^3.3^4\left(1-2^2.3^4.5\right)}\)
\(=\dfrac{2^5.5^3.3^4.1}{2^6.5^3.3^4\left(1-810\right)}\)
\(=\dfrac{1}{2.\left(-809\right)}\)
\(=-\dfrac{1}{1618}\)
a)
\(\left(\frac{x-1}{4}\right)^2=\frac{4}{9}\)
⇒ \(\frac{x-1}{4}=\frac{2}{3}\)
\(\Rightarrow\frac{\left(x-1\right).3}{12}=\frac{8}{12}\)
=> (x - 1) = 8/3
=> x = 8/3 - 1
=> x = 5/3
a) (2x)5 : 43 = 815 => 25x = 815.43 = (23)15.(22)3 = 245.26 = 251 => 5x = 51 => x = 10,2
b) (32)x .93 = 2439 => 32x = 2439 : 93 = (35)9 : (32)3 = 345 : 36 = 339 => 2x = 39 => x = 19,5
c) (1/125)3.5x = 255 => 5x = 255 : (1/125)3 = (52)5 : (1/53)3 = 510 : (5-3)3 = 510 : 5-9 = 519 => x = 19
d) 1/81 : 3x = 1/729 => 3x = 1/81 : 1/729 = 1/34.729 = 3-4.36 = 32 => x = 2
e) (5x - 2)4 = 168 = (162)4 = 2564
=> 5x - 2 = -256 ; 256 => 5x = -254 ; 258 => x = -50,8 ; 51,6
P/S : Thay x = 10,2 vào câu a , x = 19,5 vào câu b sẽ thấy điều hư cấu : 210,2 và 919,5.Ko thể tính được giá trị của 2 lũy thừa này.
TÌM X:
a) 2x - 3 = \(\frac{1}{2}\)
2x = \(\frac{1}{2}+3\)
2x = \(\frac{7}{2}\)
x = 2 : \(\frac{7}{2}\)
x = 2 . \(\frac{2}{7}\)
x = \(\frac{4}{7}\)
b) /x+1/ = 0.25
/x+1/ = \(\frac{1}{4}\)
\(\orbr{\begin{cases}x+1=\frac{1}{4}\\x+1=-\frac{1}{4}\end{cases}}\)
\(\orbr{\begin{cases}x=\frac{1}{4}-1\\x=-\frac{1}{4}-1\end{cases}}\)
\(\orbr{\begin{cases}x=-\frac{3}{4}\\x=-\frac{5}{4}\end{cases}}\)
c) 32 : 2x = 2
\(2x=32:2\)
\(2x=16\)
\(x=16:2\)
\(x=8\)
~GOOD STUDY~
a) \(5^n.25=125^2\)
\(\Rightarrow5^n.5^2=\left(5^3\right)^2\)
\(\Rightarrow5^n.5^2=5^6\)
\(\Rightarrow5^n=5^6:5^2\)
\(\Rightarrow5^n=5^4\)
\(\Rightarrow n=4\)
Vậy \(n=4.\)
b) \(3^n.9^2=27^3\)
\(\Rightarrow3^n.\left(3^2\right)^2=\left(3^3\right)^3\)
\(\Rightarrow3^n.3^4=3^9\)
\(\Rightarrow3^n=3^9:3^4\)
\(\Rightarrow3^n=3^5\)
\(\Rightarrow n=5\)
Vậy \(n=5.\)
c) \(2^4.4^n=8^6\)
\(\Rightarrow\left(2^2\right)^2.4^n=2^{18}\)
\(\Rightarrow4^2.4^n=\left(2^2\right)^9\)
\(\Rightarrow4^2.4^n=4^9\)
\(\Rightarrow4^n=4^9:4^2\)
\(\Rightarrow4^n=4^7\)
\(\Rightarrow n=7\)
Vậy \(n=7.\)
Chúc bạn học tốt!
a, x:(1/2)3=-1/2
x:1/8= -1/2
x= -1/2.1/8
x=-1/16
b,(3/4)5.x=(3/4)7
x=(3/4)7:(3/4)5
x= (3/4)2
c,(2/5)^8:x=(2/5)^6
x=.......
như cái trên nha lm giống thế
1.
a/ 1253 : 93 = \(\left(\frac{125}{9}\right)^3\) = \(\frac{1953125}{729}\)
b/ 324. 43 = \(\left(2^5\right)^4.\left(2^2\right)^3\) = \(2^{20}.2^6\) = \(2^{26}\) =67108864
2. \(\left(x+\frac{1}{2}\right)^2=\frac{4}{25}\)
=> \(\left(x+\frac{1}{2}\right)^{ }=\frac{2^2}{5^2}\)
=>\(\left(x+\frac{1}{2}\right)^2=\left(\frac{2}{5}\right)^2\)
=> \(x+\frac{1}{2}=\frac{2}{5}\)
=> \(x=\frac{2}{5}-\frac{1}{2}=\frac{-1}{10}\)
Vậy \(x=\frac{-1}{10}\)