Question $6)$

Find the given limit or show it does not exist

a$.$

$\underset{x2}{lim}\frac{x^2-3x}{x1}$

b$.$

$\underset{x1}{lim}\frac{x^{2}x-2}{x^2-1}$

c$.$

$\underset{x0}{lim}(2-\frac{1}{x^3})$

d$.$

$\underset{x-}{lim}\frac{x^{4}3x^2-2x7}{x^{3}x1}$