tìm x, biết (chú ý: m. phần cuối là 131-2 . (-5) nha giúp em từ phần h-q đc khum ạ,
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GN
GV Nguyễn Trần Thành Đạt
Giáo viên
7 tháng 1
\(\left(-2023\right).2024-2023.\left(10-2024\right)\\ =-2023.2024-2023.10+2023.2024\\ =\left(2023.2024-2023.2024\right)-2023.10\\ =0-2023.10=-20230\\ ---\\ 198.246-246.\left(198-19\right)\\ =198.246-246.198+246.19\\ =0-246.19=-4674\\ ---\\ 297.\left(435-24\right)-435.\left(297-24\right)\\ =297.435-297.24-435.297+435.24\\ =\left(297.435-435.297\right)+\left(435.24-297.24\right)\\ =0+\left(435-297\right).24\\ =0+138.24=3312\\ ----\\ \left(-367\right).\left(19-198\right)+198.\left(19-367\right)\\ =-367.19+367.198+198.19-367.198\\ =\left(367.198-367.198\right)+\left(198.19-367.19\right)\\ =0+19.\left(198-367\right)=0+19.\left(-169\right)=-3211\)
N
0
3 tháng 10 2023
a) \(\dfrac{81}{\left(-3\right)^n}=-243\)
\(\dfrac{\left(-3\right)^4}{\left(-3\right)^n}=\left(-3\right)^5\)
\(\left(-3\right)^n=\dfrac{\left(-3\right)^4}{\left(-3\right)^5}=\left(-3\right)^{-1}\)
n = -1
Vậy n = -1
b) \(\dfrac{25}{5^n}=5\)
\(\dfrac{5^2}{5^n}=5^1\)
\(5^n=\dfrac{5^2}{5^1}=5^1\)
n = 1
Vậy n = 1
c) \(\dfrac{1}{2}\cdot2^n+4\cdot2^n=9\cdot2^5\)
\(2^{n-1}+4\cdot2^{n-1}\cdot2=9\cdot2^5\)
\(2^{n-1}+8\cdot2^{n-1}=9\cdot2^5\)
\(\left(8+1\right)\cdot2^{n-1}=9\cdot2^5\)
\(9\cdot2^{n-1}=9\cdot2^5\)
\(2^{n-1}=2^5\cdot\dfrac{9}{9}=2^5\)
n - 1 = 5
n = 5 + 1 = 6
Vậy n = 6
KV
3 tháng 10 2023
a) 81/(-3)ⁿ = -243
(-3)ⁿ = 81 : (-243)
(-3)ⁿ = -1/3
n = -1
b) 25/5ⁿ = 5
5ⁿ = 25 : 5
5ⁿ = 5
n = 1
c) 1/2 . 2ⁿ + 4 . 2ⁿ = 9 . 2⁵
2ⁿ . (1/2 + 4) = 9 . 32
2ⁿ . 9/2 = 288
2ⁿ = 288 : 9/2
2ⁿ = 64
2ⁿ = 2⁶
n = 6
DD
1 tháng 1 2016
\(\left(1+\frac{1}{5}\right)\cdot\left(1+\frac{1}{6}\right)\cdot....+\left(1+\frac{1}{2014}\right)\)
=\(\frac{6}{5}\cdot\frac{7}{6}\cdot...\cdot\frac{2015}{2014}\)
=\(\frac{2015}{5}\)
=403
BN
3
27 tháng 6 2017
bạn ơi nếu đây là toán lớp 5 thì riêng x - x = 0 rồi đề bài sai bn ơi
TN
15 tháng 6 2017
Ta có:
\(\left(\frac{1}{5}+\frac{1}{3}+\frac{3}{10}\right)+-\frac{1}{2}=\frac{1}{5}+\frac{1}{3}+\frac{3}{10}\)\(-\frac{1}{2}\)
=\(\frac{6}{30}+\frac{10}{30}+\frac{9}{30}-\frac{15}{30}=\frac{6+10+9-15}{30}=\frac{10}{30}=\frac{1}{3}\)
30 tháng 6 2018
10+x/17+x=3/4
<=>x/17+x=10+3/4
<=>x(1/17+1)=43/4
<=>x*18/17=43/4
=>x=43/4:18/17=....
Còn lại bạn tính nhé
G
1
3 tháng 1
`#3107.101107`
\(\left(\dfrac{2}{3}\right)^x+\left(\dfrac{2}{3}\right)^{x+2}=\dfrac{104}{243}?\)
\(\Rightarrow\left(\dfrac{2}{3}\right)^x+\left(\dfrac{2}{3}\right)^x\cdot\left(\dfrac{2}{3}\right)^2=\dfrac{104}{243}\)
\(\Rightarrow\left(\dfrac{2}{3}\right)^x\cdot\left(1+\dfrac{2^2}{3^2}\right)=\dfrac{104}{243}\)
\(\Rightarrow\left(\dfrac{2}{3}\right)^x\cdot\left(1+\dfrac{4}{9}\right)=\dfrac{104}{243}\)
\(\Rightarrow\left(\dfrac{2}{3}\right)^x\cdot\dfrac{13}{9}=\dfrac{104}{243}\)
\(\Rightarrow\left(\dfrac{2}{3}\right)^x=\dfrac{104}{243}\div\dfrac{13}{9}\)
\(\Rightarrow\left(\dfrac{2}{3}\right)^x=\dfrac{8}{27}\)
\(\Rightarrow\left(\dfrac{2}{3}\right)^x=\dfrac{2^3}{3^3}\)
\(\Rightarrow\left(\dfrac{2}{3}\right)^x=\left(\dfrac{2}{3}\right)^3\)
\(\Rightarrow x=3\)
Vậy, `x = 3.`
h: \(\left(-145\right)-5\left(2x-1\right)^3=480\)
=>\(5\left(2x-1\right)^3=-145-480\)=-625
=>(2x-1)3=-125
=>2x-1=-5
=>2x=-5+1=-4
=>x=-4/2=-2
k: \(3\left(-4+x\right)^3-\left(-4\right)^2=-97\)
=>\(3\left(x-4\right)^3-16=-97\)
=>\(3\cdot\left(x-4\right)^3=-97+16=-81\)
=>\(\left(x-4\right)^3=-27\)
=>x-4=-3
=>x=-3+4=1
n: \(195+3\left(-2x+5\right)^3=192\)
=>\(3\left(-2x+5\right)^3=192-195=-3\)
=>\(\left(-2x+5\right)^3=-1\)
=>-2x+5=-1
=>-2x=-1-5=-6
=>\(x=\dfrac{-6}{-2}=3\)
o: \(\left(-148\right)-5\left(-x+6\right)^4=-228\)
=>\(148+5\left(x-6\right)^4=228\)
=>\(5\left(x-6\right)^4=80\)
=>\(\left(x-6\right)^4=16\)
=>\(\left[{}\begin{matrix}x-6=2\\x-6=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=8\\x=4\end{matrix}\right.\)
p: \(-43-\left(-4+x\right)^4=-44\)
=>\(\left(x-4\right)^4+43=44\)
=>\(\left(x-4\right)^4=1\)
=>\(\left[{}\begin{matrix}x-4=1\\x-4=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=3\end{matrix}\right.\)
q: \(3\left(-x+5\right)^2-\left(-5\right)^2\cdot\left(-2\right)^3=203\)
=>\(3\left(x-5\right)^2-25\cdot\left(-8\right)=203\)
=>\(3\left(x-5\right)^2+200=203\)
=>\(3\left(x-5\right)^2=3\)
=>(x-5)2=1
=>\(\left[{}\begin{matrix}x-5=1\\x-5=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=6\\x=4\end{matrix}\right.\)
h.
$(-145)-5(2x-1)^3=480$
$5(2x-1)^3=-145-480=-625$
$(2x-1)^3=-625:5=-125=(-5)^3$
$\Rightarrow 2x-1=-5$
$\Rightarrow x=-3$
k.
$3(-4+x)^3-(-4)^2=-97$
$3(-4+x)^3-16=-97$
$3(-4+x)^3=-97+16=-81$
$(-4+x)^3=-81:3=-27=(-3)^3$
$\Rightarrow -4+x=-3$
$\Rightarrow x=-3-(-4)=1$