Question

Tìm GTLN hoặc GTNN của:

a) \(A=\left|-x+8\right|—21\)

b) \(B=\left|-x-17\right|+\left|y-36\right|+12\)

c) \(C=-\left|2x+8\right|-35\)

d) \(D=3\left(3x-12\right)^2-37\)

e) \(E=-21-3.\left|2x+50\right|\)

g) \(G=\left(x-3\right)^2+\left|x^2-9\right|+25\)

Answer 1

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

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

\(MinA=-21\Leftrightarrow-x+8=0\)\(\Leftrightarrow x=8\)

\(B=\left|-x-17\right|+\left|y-36\right|+12\)

\(B=\left|-x-17\right|+\left|y-36\right|+12\ge12\)

\(MinB=12\Leftrightarrow\hept{\begin{cases}-x-17=0\\y-36=0\end{cases}}\Leftrightarrow\hept{\begin{cases}x=-17\\y=36\end{cases}}\)

\(C=-\left|2x+8\right|-35\)

\(C=-\left|2x+8\right|-35\le-35\)

\(MaxC=-35\Leftrightarrow2x+8=0\Leftrightarrow x=-4\)

Answer 2

Trl

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