Ta có \(x\left(4x+2\right)-\left(2x-5\right)\left(2x+5\right)=1\)
\(\Leftrightarrow4x^2+2x-\left(4x^2-25\right)=1\)
\(\Leftrightarrow4x^2+2x-4x^2+25=1\)
\(\Leftrightarrow2x=-24\)
\(\Leftrightarrow x=-12\)
Vậy x=-12
\(x\left(4x+2\right)-\left(2x-5\right)\left(2x+5\right)=1\)
\(4x^2+2x-\left(\left(2x\right)^2-5^2\right)=1\)
\(4x^2+2x-4x^2+25=1\)
\(2x+25=1\)
\(2x=-24\)
\(x=-12\)