mk làm nhanh! giải rõ hơn nha

1/\(\left(2x-5\right)\left(2x-1\right)=0\Rightarrow\left[{}\begin{matrix}x=\frac{5}{2}\\x=\frac{1}{2}\end{matrix}\right.\)

2/\(\left(x+1\right)\left(2x+3\right)=0\Rightarrow\left[{}\begin{matrix}x=-1\\x=-\frac{3}{2}\end{matrix}\right.\)

3/\(\left(x-1\right)\left(x+2\right)=0\Rightarrow\left[{}\begin{matrix}x=1\\x=-2\end{matrix}\right.\)

4/\(\left(x-3\right)\left(x-1\right)=0\Rightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)

5/\(\left(2x-1\right)\left(x+3\right)=0\Rightarrow\left[{}\begin{matrix}x=\frac{1}{2}\\x=-3\end{matrix}\right.\)

6/\(\left(x-2\right)\left(x+8\right)=0\Rightarrow\left[{}\begin{matrix}x=2\\x=-8\end{matrix}\right.\)

Đặt t = 2 x ( t > 0 ) nhận được phương trình  t 2 - 8 t + 12 = 0

Tích hai nghiệm bằng  1 + log 3 log 2

Chọn C

  A = (5\(x\) + 1)² + (5\(x\) - 1)² - 2.( 5\(x\) +1).(5\(x\) - 1) tại \(x\) = 1

Thay \(x\) = 1 vào A ta có:

A = (5.1 + 1)² + (5.1 - 1)² - 2.(5.1 + 1).(5.1 - 1)

A = 6² + 4² - 2.6.4 

A = 36 + 16 - 48

A = 52 - 48

A = 4

\(\left(5x-1\right)^2+2\left(1-5x\right)\left(4+5x\right)+\left(5x+4\right)^2\)

\(=\left(5x-1\right)^2-2\left(5x-1\right)\left(5x+4\right)+\left(5x+4\right)^2\)

\(=\left[\left(5x-1\right)-\left(5x+4\right)\right]^2\)

\(=\left(5x-1-5x-4\right)^2\)

\(=\left(-5\right)^2\)

\(=25\)

Ai giúp mình với. Mình tích cho ạ

\(\dfrac{3}{{5x - 1}} + \dfrac{2}{{3 - 5x}} = \dfrac{4}{{\left( {1 - 5x} \right)\left( {x - 3} \right)}}\)

ĐKXĐ: \(x \ne \dfrac{1}{5};x\ne \dfrac{3}{5};x \ne 3\)

\( \Leftrightarrow 3\left( {3 - 5x} \right)\left( {x - 3} \right) + 2\left( {5x - 1} \right)\left( {x - 3} \right) + 4\left( {3 - 5x} \right) = 0\\ \Leftrightarrow 9x - 27 - 15{x^2} + 45x + 10{x^2} - 30x - 2x + 6 + 12 - 20x = 0\\ \Leftrightarrow - 5{x^2} + 2x - 9 = 0 \)

\(\Rightarrow\) Phương trình vô nghiệm.

\(5^x+5^{x+1}+5^{x+2}+5^{x+3}=1+2+3+...+87+88-4^2\)

=>\(5^x+5^x\cdot5+5^x\cdot25+5^x\cdot125=88\cdot\dfrac{\left(88+1\right)}{2}-16\)

=>\(156\cdot5^x=44\cdot89-16=3900\)

=>\(5^x=\dfrac{3900}{156}=25\)

=>x=2

Chọn B