Question

[Hương Ly Đào]

x² - 14x + 13= 0

các cậu giúp tớ giải 1 câu này với :(((

Answer 1

[Trần Thùy Dương]

\(x^2-14x+13=0\)

\(\Rightarrow x^2-2x.7+7^2-7^2+13=0\)

\(\Rightarrow\left(x^2-2x.7+7^2\right)-7^2+13=0\)

\(\Rightarrow\left(x-7\right)^2-49+13=0\)

\(\Rightarrow\left(x-7\right)^2-36=0\)

\(\Rightarrow\left(x-7\right)^2=36\)

\(\Rightarrow\left(x-7\right)^2=\pm6^2\)

\(\Rightarrow\orbr{\begin{cases}x-7=6\\x-7=-6\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=13\\x=1\end{cases}}\)

Vậy ...

Answer 2

[๖ۣۜFunny-Ngốkツ]

\(x^2-14x+13=0\)

\(x^2-14x+49-36=0\)

\(\left(x^2-14x+19\right)-36=0\)

\(\left(x-7\right)^2-6^2=0\)

\(\left(x-7-6\right)\left(x-7+6\right)=0\)

\(\left(x-13\right)\left(x-1\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x-13=0\\x-1=0\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=13\\x=1\end{cases}}\)