(a) $\log_{2}{\left( x^{2} - 3x + 18 \right) < 4}$ $\Rightarrow x^{2} - 3x + 18 < 16\ \ \ \ ($If$\log_{a}{b < c \Rightarrow b < a^{c})}$ $\Rightarrow x^{2} - 3x + 2 < 0$ $\Rightarrow (x - 1)(x - 2) < 0$ $\Rightarrow x \in (1,\ 2)$
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.