\(\Leftrightarrow\left(x+3\right)^2=25-3\cdot\left(-8\right)=25+24=49\)
\(\Leftrightarrow\left[{}\begin{matrix}x+3=7\\x+3=-7\end{matrix}\right.\Leftrightarrow x\in\left\{4;-10\right\}\)
25-(3+x)2=3(-2)3
25-(3+x)2=-24
(3+x)2=25+24
(3+x)2=49=72
3+x=7
x=7-3
x=4
vậy ...
\(25-\left(3+x\right)^2=3.\left(-2\right)^3.\)
\(\Leftrightarrow25-9-6x-x^2=3.\left(-8\right).\)
\(\Leftrightarrow16-6x-x^2+24=0.\)
\(\Leftrightarrow-x^2-6x+40=0.\)
\(\Leftrightarrow\left(x-4\right)\left(x+10\right)=0.\)
\(\Leftrightarrow\left[{}\begin{matrix}x-4=0.\\x+10=0.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4.\\x=-10.\end{matrix}\right.\)
