Question

Tìm GTLN hoặc GTNN: A= |-x +8|-21

Answer 1

http://123link.vip/VNybjKzt

Answer 2

\(A=\left|-x+8\right|-21\)

Vì \(\left|-x+8\right|\le0\forall x\)

\(A=\left|-x+8\right|-21\ge21\)

\(\Rightarrow A_{max}=-21\)khi \(\left|-x+8\right|=0\Rightarrow-x+8=0\Rightarrow-x=-8\Rightarrow x=8\)

Vậy với A_min = -21 khi x = 8

Answer 3

\(A=\left|-x+8\right|-21\)

Vì \(\left|-x+8\right|\ge0\forall x\)

\(\Rightarrow A\ge-21\forall x\)

Dấu "=" xảy ra \(\Leftrightarrow-x+8=0\Leftrightarrow x=8\)

Vậy....