\(H\left(x\right)=x+3\)
\(\Rightarrow H\left(x\right)=0\Leftrightarrow x+3=0\Rightarrow x=-3\)
\(T\left(x\right)=12-\dfrac{1}{3}x\)
\(\Rightarrow T\left(x\right)=0\Leftrightarrow12-\dfrac{1}{3}x=0\Rightarrow\dfrac{1}{3}x=12\Rightarrow x=36\)
\(B\left(x\right)=x^2-5x+4=\left(x-1\right)\left(x-4\right)\)
\(\Rightarrow B\left(x\right)=0\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x-4=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=1\\x=4\end{matrix}\right.\)
\(C\left(x\right)=42x-4x^2=2x\left(21-2x\right)\)
\(\Rightarrow C\left(x\right)=0\Leftrightarrow\left[{}\begin{matrix}2x=0\\21-2x=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0\\x=10\dfrac{1}{2}\end{matrix}\right.\)
MONG CÂU TRẢ LỜI NÀY GIÚP BN
#chúc_bn_học_tốt
