Zaza, tự làm nữa đi a~.
a) \(3x\left(x-8\right)+16=2x\)
\(\Rightarrow3x^2-24x+16=2x\)
\(\Rightarrow3x^2-26x+16=0\)
\(\Rightarrow\left(3x^2-24x\right)-\left(2x-16\right)=0\)
\(\Rightarrow3x\left(x-8\right)-2\left(x-8\right)=0\)
\(\Rightarrow\left(x-8\right)\left(3x-2\right)=0\)
Để đẳng thức xảy ra \(\Rightarrow\left[\begin{array}{nghiempt}x-8=0\\3x-2=0\end{array}\right.\)\(\Rightarrow x\in\left\{8;\frac{2}{3}\right\}\)
b) \(\left(5-x\right)^2=25=5^2=\left(-5\right)^2\)
\(\Rightarrow5-x\in\left\{\pm5\right\}\Rightarrow x\in\left\{0;10\right\}\)