Question:
The binary operation $*$ on $\mathrm{R}$ is defined by $\mathrm{a} * \mathrm{~b}=2 \mathrm{a}+\mathrm{b}$. Find $(2 * 3) * 4$.
Solution:
To find: $(2 * 3) * 4$
Given: $a * b=2 a+b$
$\Rightarrow 2 * 3=2 \times 2+3=7$
Now $7 * 4=2 \times 7+4=14+4=18$
$\Rightarrow(2 * 3) * 4=18$