b: ta có: \(x^2-5x=-6\)
\(\Leftrightarrow x^2-5x+6=0\)
=>(x-2)(x-3)=0
=>x=2 hoặc x=3
c: Sửa đề: \(\left(2x-1\right)^2-\left(3x+5\right)^2=0\)
\(\Leftrightarrow\left(2x-1-3x-5\right)\left(2x-1+3x+5\right)=0\)
\(\Leftrightarrow\left(-x-6\right)\left(5x+4\right)=0\)
=>x=-6 hoặc x=-4/5
d: ta có: \(4x^2-20x+25=0\)
\(\Leftrightarrow\left(2x-5\right)^2=0\)
=>2x-5=0
hay x=5/2
e: \(\Leftrightarrow\left(3x-1-x+2\right)\left(3x-1+x-2\right)=0\)
\(\Leftrightarrow\left(2x+1\right)\left(4x-3\right)=0\)
hay \(x\in\left\{-\dfrac{1}{2};\dfrac{3}{4}\right\}\)