Question

一、225 + 4.8 I don’t understand it plz help (And do it step by step...)

Answer 1

$\bf -\sqrt{225}+4.8~~ \begin{cases} 225=&3\cdot 3\cdot 5\cdot 5\\ &3^2\cdot 5^2\\ &(3\cdot 5)^2\\ &15^2 \end{cases}\\\\\\ -\sqrt{15^2}+4.8\implies -15+4.8\implies -10.2$