a, \(P\left(x\right)=4x-\dfrac{1}{2}\)
\(\Rightarrow P\left(x\right)=4x-\dfrac{1}{2}=0\)
\(\Rightarrow x=\dfrac{1}{8}\)
b, \(Q\left(x\right)=\left(x-1\right)\left(x+1\right)\)
\(\Rightarrow Q\left(x\right)=\left(x-1\right)\left(x+1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-1=0\\x+1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=1\\x=-1\end{matrix}\right.\)
c, \(A\left(x\right)=x^2-7x+6\)
\(\Rightarrow A\left(x\right)=x^2-7x+6=0\)
\(\Rightarrow x^2-6x-x+6=0\)
\(\Rightarrow x\left(x-6\right)-\left(x-6\right)=0\)
\(\Rightarrow\left(x-6\right)\left(x-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-6=0\\x-1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=6\\x=1\end{matrix}\right.\)
a) x=0,125
b) x=1 hoặc x= \(-1\)
c) x=1 hoặc x=6
d) x=4 hoặc x=\(-4\)
e)\(x\in\varnothing\)