Question

Tìm GTNN: 4X^2_+4X-5

Answer 1

\(4x^2+4x-5=\left(4x^2+4x+1\right)-6\)

\(=\left(2x+1\right)^2-6\ge-6\)

Dấu "=" xảy ra \(\Leftrightarrow x=-\dfrac{1}{2}\)