[tex]\begin{gathered} a^2+3=19 \\ a^2+3-3=19-3\text{ (Subtracting 3 on both sides of the equation)} \\ a^2=16 \\ \sqrt[]{a^2}=\sqrt[]{16}\text{ (Calculating the root of each term)} \\ a=4\text{ or a=-4} \\ Answer\rightarrow a=\mleft\lbrace4,-4\mright\rbrace \end{gathered}[/tex]
