Chuyển vế -25 thành 25 rồi dùng hdt số 1
x2-10x_25=0
\(\Rightarrow\)\(\left\{{}\begin{matrix}x=5\\\end{matrix}\right.\)
\(\Leftrightarrow x^2-10x+25=0\)
\(\Leftrightarrow\left(x-5\right)^2=0\)
\(\Leftrightarrow x-5=0\)
\(\Leftrightarrow x=5\)
\(x^2-10x=-25\\ \Rightarrow x^2-10x+25=0\\ \Rightarrow x^2-2.5.x+5^2=0\\ \Rightarrow\left(x-5\right)^2=0\\ \Rightarrow x-5=0\\ \Rightarrow x=5\)
x^2-10x=-25
<=>x^2-10x+25=0
<=>(x-5)^2=0
<=>x-5=0
<=>x=5
Vậy x=5