Câu 4:
c: \(\Leftrightarrow\left(x-4\right)\left(x+4-1\right)=0\)
=>(x-4)(x+3)=0
=>x=4 hoặc x=-3
d: \(\Leftrightarrow\left(x-5\right)\left(6x-1\right)=0\)
=>x=5 hoặc x=1/6
e: \(\Leftrightarrow x^3-x-6x-6=0\)
\(\Leftrightarrow x\left(x-1\right)\left(x+1\right)-6\left(x+1\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(x^2-x-6\right)=0\)
=>(x+1)(x-3)(x+2)=0
hay \(x\in\left\{-1;3;-2\right\}\)

