Q$5.$

a$)y=e^{-3x^2},$ Find $\frac{d^{2}y}{d{x}^2}$

b$)y=-\frac{1}{2}{e}^{2x}+2e^{-x},$ Find $\frac{d^{2}y}{d{x}^2}$

c$)y=(x^3-5)(2x+3),$ Find $\frac{d^{2}y}{d{x}^2}$