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1) Tìm số nguyên x, biết :
a) 3x = 94/ 273
3x = 1/3
3x = 3-1
=> x = -1
b) 3x = 98 / 273 . 812
3x = 37.38
3x = 315
=> x = 15
c) 2x - 3 / 410 = 83
2x - 3 = 83.410
2x - 3 = 226
=> x - 3 = 26
=> x = 29
d) 22x - 3 / 410 = 83 . 165
22x - 3 / 410 = 269
22x - 3 = 269 . 410
22x - 3 = 289
=> 2x - 3 = 89
2x = 91
x = 91/2
e) 35 / 3x = 310
3x = 35 : 310
3x = 3-5
=> x = -5
\(\Rightarrow3^{2x+1}=\frac{9^4}{9^2}\)
\(\Rightarrow3^{2x+1}=9^2\)
\(\Rightarrow2x+1=4\)
\(\Rightarrow2x=3\)
\(\Rightarrow x=\frac{3}{2}\)
\(3^{2x-1}=9^2\)
\(3^{2x-1}=3^4\)
\(\Rightarrow2x-1=4\)
\(2x=4+1\)
\(\left(\frac{1}{4}\right)^{44}.\left(\frac{1}{2}\right)^{12}=\left(\left(\frac{1}{2}\right)^2\right)^{44}.\left(\frac{1}{2}\right)^{12}=\left(\frac{1}{2}\right)^{88}.\left(\frac{1}{2}\right)^{12}=\left(\frac{1}{2}\right)^{100}\)
\(\frac{3^{17}.\left(3^4\right)^{11}}{\left(3^3\right)^{10}.\left(3^2\right)^{15}}=\frac{3^{17}.3^{44}}{3^{30}.3^{30}}=\frac{3^{61}}{3^{60}}=3\)
1/vì (1,782x-2-1,78x):1,78x=0
nên 1,78x2-2-1,78x=0
=>1,782x-2=1,78x
=>2x-2=x
2x=x+2
=>x=2
2/vì cơ số bằng nhau nên ta có
x-2=1;-1;0
ta có: x-2=1 => x=3
x-2=-1 => x=1
x-2=0 => x=2
3/ta có
(x+2)3=33 =>x+2=3 =>x=1
mik mệt rồi bạn cứ gải tiếp đi
1, 27x.9x=927:81
(33)x.(32)X=(32)27:34
33X.32X=354:34
33X+2X=350
35X=350
Suy ra :5x=50
x=10
e)
\(\left(-\frac{3}{4}\right)^{3x-1}=\frac{256}{81}\)
\(\left(-\frac{3}{4}\right)^{3x}=\left(-\frac{4}{3}\right)^4\)
\(\left(-\frac{3}{4}\right)^{3x}=\left(-\frac{3}{4}\right)^{-4}\)
\(3x=-4\)
\(x=-\frac{4}{3}\)
f) \(172x^2-7^9:98^3=2^{-3}\)
\(172x^2-\frac{7^9}{\left(7^2.2\right)^3}=\frac{1}{2^3}\)
\(172x^2-\frac{7^3}{2^3}=\frac{1}{2^3}\)
\(172x^2=\frac{7^3}{2^3}+\frac{1}{2^3}=\frac{344}{8}\)
\(x^2=\frac{344}{8}:172=\frac{1}{4}\)
x=1/2 hoặc x=-1/2
a) Ta có \(\left(2^{17}+17^2\right)\cdot\left(9^{15}-15^9\right)\cdot\left(4^2-2^4\right)\)
=\(\left(2^{17}+17^2\right)\cdot\left(9^{15}-15^9\right)\cdot\left(16-16\right)\)
=\(\left(2^{17}+17^2\right)\cdot\left(9^{15}-15^9\right)\cdot0\)=0
b) \(\left(7^{1997}-7^{1995}\right):\left(7^{1994}\cdot7\right)\)
=\(\left(7^{1995}\left(7^2-1\right)\right):7^{1995}\)
=\(7^2-1\)=\(49-1\)=\(48\)
c Giống câu a
\(81.3^{x-1}=3^3.9^4\)\(\Rightarrow3^4.3^{x-1}=3^3.3^8\)
\(\Rightarrow3^{4+x-1}=3^{3+8}\Rightarrow\)\(3^{x+3}=3^{11}\Rightarrow x+3=11\)
\(\Rightarrow x=8\). Học tốt =)
cảm ơn bạn nha