\(a.3\left(x^2-2x+1\right)-3x^2+15x-2=0\)
\(3x^2-6x+3-3x^2+15x-2=0\)
\(9x+1=0\)
\(x=-\frac{1}{9}\)
\(b.4x^2-12x+9=0\)
\(4x^2-6x-6x+9=0\)
\(2x\left(x-3\right)-3\left(x-3\right)=0\)
\(\left(2x-3\right)\left(x-3\right)=0\)
\(\Rightarrow\orbr{\begin{cases}2x-3=0\\x-3=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{3}{2}\\x=3\end{cases}}\)
\(c.\left(2x-3\right)^2-\left(x+5\right)^2=0\)
\(\left(2x-3-x-5\right)\left(2x-3+x+5\right)=0\)
\(\left(x-8\right)\left(3x+2\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-8=0\\3x+2=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=8\\x=-\frac{2}{3}\end{cases}}\)
a) 3(x - 1)2 - 3x(x - 5) = 2
=> 3(x2 - 2x + 1) - 3x2 + 15x = 2
=> 3x2 - 6x + 3 - 3x2 + 15x = 2
=> 9x = 2 - 3
=> 9x = -1
=> x = -1/9
b) 4x2 - 12x = -9
=> 4x2 - 12x + 9 = 0
=> (2x - 3)2 = 0
=> 2x - 3 = 0
=> 2x = 3
=> x = 3/2
c) (2x - 3)2 = (x + 5)2
=> (2x - 3)2 - (x + 5)2 = 0
=> (2x - 3 - x - 5)(2x - 3 + x + 5) = 0
=> (x - 8)(3x + 2) = 0
=> \(\orbr{\begin{cases}x-8=0\\3x+2=0\end{cases}}\)
=> \(\orbr{\begin{cases}x=8\\x=-\frac{2}{3}\end{cases}}\)
d) \(\left(x^4-2x^3+4x^2-8x\right):\left(x^2+4\right)-2x=-4\)
=> \(\left[x^3\left(x-2\right)+4x\left(x-2\right)\right]:\left(x^2+4\right)-2x=-4\)
=> \(x\left(x-2\right)\left(x^2+4\right):\left(x^2+4\right)-2x=-4\)
=> \(x^2-2x-2x+4=0\)
=> \(\left(x-2\right)^2=0\)
=> x - 2 = 0
=> x = 2
e) khđ
