Question
If the operation $\star$ is defined by $a \star b = a^2 + b^2$ for all real numbers $a$ and $b$, then $(2 \star 3) \star 4 = \_\_\_\_)$
If the operation $\star$ is defined by $a \star b = a^2 + b^2$ for all real numbers $a$ and $b$, then $(2 \star 3) \star 4 = \_\_\_\_)$