Limits Continuity And Differentiability

If \(f(x)\) is continuous on its domain \([-2,2]\), where

$$f(x)=\left\{\begin{array}{cc} \frac{\sin a x}{x}+3 & , \text { for }-2 \leq x<0 \\ 2 x+7 & , \text { for } 0 \leq x \leq 1 \\ \sqrt{x^2+8}-b & , \text { for } 1< x \leq 2 \end{array}\right.$$ \(\text { then the value of } 2 a+3 b \text { is }\)