Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a)\(\left(2x+3\right)^2=\frac{9}{121}\\ \Leftrightarrow\left(2x+3\right)^2=\left(\pm\frac{3}{11}\right)^2\\ \Rightarrow\left\{{}\begin{matrix}2x+3=\frac{3}{11}\\2x+3=\frac{-3}{11}\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=\frac{-15}{11}\\x=\frac{-18}{11}\end{matrix}\right.\)
Vậy...
b)\(\left(3x-1\right)^3=\frac{-8}{27}\\ \Leftrightarrow\left(3x-1\right)^3=\left(\frac{-2}{3}\right)^3\\ 3x-1=\frac{-2}{3}\\ \Rightarrow x=\frac{1}{9}\)
Vậy...
a) \(\left(2x+3\right)^2=\frac{9}{121}\)
\(\Rightarrow2x+3=\pm\frac{3}{11}\)
\(\Rightarrow\left[{}\begin{matrix}2x+3=\frac{3}{11}\\2x+3=-\frac{3}{11}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}2x=\frac{3}{11}-3=-\frac{30}{11}\\2x=\left(-\frac{3}{11}\right)-3=-\frac{36}{11}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\left(-\frac{30}{11}\right):2\\x=\left(-\frac{36}{11}\right):2\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=-\frac{15}{11}\\x=-\frac{18}{11}\end{matrix}\right.\)
Vậy \(x\in\left\{-\frac{15}{11};-\frac{18}{11}\right\}.\)
b) \(\left(3x-1\right)^3=-\frac{8}{27}\)
\(\Rightarrow\left(3x-1\right)^3=\left(-\frac{2}{3}\right)^3\)
\(\Rightarrow3x-1=-\frac{2}{3}\)
\(\Rightarrow3x=\left(-\frac{2}{3}\right)+1\)
\(\Rightarrow3x=\frac{1}{3}\)
\(\Rightarrow x=\frac{1}{3}:3\)
\(\Rightarrow x=\frac{1}{9}\)
Vậy \(x=\frac{1}{9}.\)
Chúc bạn học tốt!
e)
\(\left(x+3\right)^3=\left(x+3\right)^5\)
\(\Rightarrow\)\(x+3=1;0\)
TH1: TH2
\(x+3=0\) \(x+3=1\)
\(x=-3\) \(x=-2\)
\(x\in\left\{-3;-2\right\}\)
a) Vì \(\left(2.x+3\right)^2=\dfrac{9}{121}\Rightarrow\left\{{}\begin{matrix}2.x+3=\dfrac{3}{11}\\2.x+3=-\dfrac{3}{11}\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=-\dfrac{15}{11}\\x=-\dfrac{18}{11}\end{matrix}\right.\)
b) Vì \(\left(3.x-1\right)^3=-\dfrac{8}{27}\Rightarrow3.x-1=-\dfrac{2}{3}\Rightarrow x=\dfrac{1}{9}\)
a) \(\left(-\frac{3}{4}\right)^{3x-1}=\frac{-27}{64}\)
\(\Leftrightarrow\left(-\frac{3}{4}\right)^{3x-1}=\left(-\frac{3}{4}\right)^3\)
\(\Leftrightarrow3x-1=3\)
\(\Leftrightarrow3x=4\)
\(\Leftrightarrow x=\frac{4}{3}\)
b) Đề sai ! Sửa :
\(\left(\frac{4}{5}\right)^{2x+5}=\frac{256}{625}\)
\(\Leftrightarrow\left(\frac{4}{5}\right)^{2x+5}=\left(\frac{4}{5}\right)^4\)
\(\Leftrightarrow2x+5=4\)
\(\Leftrightarrow2x=-1\)
\(\Leftrightarrow x=-\frac{1}{2}\)
c) \(\frac{\left(x+3\right)^5}{\left(x+5\right)^2}=\frac{64}{27}\)
\(\Leftrightarrow\left(x+3\right)^3=\left(\frac{4}{3}\right)^3\)
\(\Leftrightarrow x+3=\frac{4}{3}\)
\(\Leftrightarrow x=-\frac{5}{3}\)
d) \(\left(x-\frac{2}{15}\right)^3=\frac{8}{125}\)
\(\Leftrightarrow\left(x-\frac{2}{15}\right)^3=\left(\frac{2}{15}\right)^3\)
\(\Leftrightarrow x-\frac{2}{15}=\frac{2}{15}\)
\(\Leftrightarrow x=\frac{4}{15}\)
biết giải bài 2
x/12=y/14=x.y/12.24=98/288=49/144
=> x/12=49/144=> 49/12
=> y/14=49/144=> 343/72
mới lớp 2 thôi
a/ \(\Rightarrow x^{10}-25x^8=0\Rightarrow x^8\left(x^2-25\right)=0\)
\(\Rightarrow x^8=0\Rightarrow x=0\)
hoặc \(x^2-25=0\Rightarrow x=5;x=-5\)
Vậy x = 0 ; x = 5; x = -5
b/ \(\Rightarrow2x+3=\frac{3}{11}\Rightarrow2x=-\frac{30}{11}\Rightarrow x=-\frac{15}{11}\)
hoặc \(2x+3=-\frac{3}{11}\Rightarrow2x=-\frac{36}{11}\Rightarrow x=-\frac{18}{11}\)
Vậy x = -15/11 ; x = -18/11
c/ \(\Rightarrow\left(3x-1\right)^3=\left(-\frac{2}{3}\right)^3\Rightarrow3x-1=-\frac{2}{3}\Rightarrow3x=\frac{1}{3}\Rightarrow x=\frac{1}{9}\)
Vậy x = 1/9
a, x10 = 25.x8
=> x2 = 25 = 52 = (-5)2
=> x = + 5
b, \(\left(2x+3\right)^2=\frac{9}{121}=\left(\frac{3}{11}\right)^2=\left(-\frac{3}{11}\right)^2\)
=> 2x + 3 = + \(\frac{3}{11}\)
TH1: 2x + 3 = \(\frac{3}{11}\)
=> 2x = \(\frac{-30}{11}\)
=> x = \(\frac{-15}{11}\)
TH2: 2x + 3 = \(\frac{-3}{11}\)
=> 2x = \(\frac{-36}{11}\)
=> x = \(\frac{-18}{11}\)
(3x - 1)3 = \(\frac{-8}{27}\) = \(\left(\frac{-2}{3}\right)^3\)
=> 3x - 1 = \(\frac{-2}{3}\)
=> 3x = \(\frac{1}{3}\)
=> x = \(\frac{1}{9}\)
a, \(\left(2x+3\right)^2=\frac{3^2}{11^2}\)
từ đó suy ra
\(2x+3=\frac{3}{11}\)
2x=3/11-3
2x=-2/8/11
x=-2/8/11:2
x=-1/4/11
b,
(3x-1)^3=-8/27
(3x-1)^3=(-2/3)^3
Vậy suy ra
3x-1=-2/3
3x=-2/3+1
3x=1/3
x=1/3:3
x=1/9
Ko thấy x