\(\dfrac{8^4.15^4}{12^3.10^3}=\dfrac{2^{12}.3^4.5^4}{2^6.3^3.2^3.5^3}=2^3.3.5=120\)
Vì \(-\left|2x+3\right|\le0\Rightarrow4-\left|2x+3\right|\le4\)
\(\Rightarrow A\le4\forall x\)
Dấu "=" xảy ra khi \(\left|2x+3\right|=0\Rightarrow2x+3=0\)
\(\Rightarrow x=\dfrac{-3}{2}\)
Vậy \(MAX_A=A\) khi x = -3/2.