Question

tìm x

x.(x+1)-(x-2)=11

Answer 1

=>x^2+x-x+2=11

=>x^2=9

=>x=3 hoặc x=-3

Answer 2

\(x\left(x+1\right)-\left(x-2\right)=11\)

\(\Rightarrow x^2+x-x+2=11\)

\(\Rightarrow x^2+2=11\)

\(\Rightarrow x^2=11-2\)

\(\Rightarrow x^2=9\)

\(\Rightarrow x^2=3^2\)

\(\Rightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)