Evaluate the following limits$.$ If needed, enter @$0$ for $$ and oo for $-.$

$($a$)\underset{x}{lim}\frac{\sqrt[\phantom{2}]{7+5x^2}}{3+2x}=$

$$

$($b$)\underset{x-}{lim}\frac{\sqrt[\phantom{2}]{7+5x^2}}{3+2x}=$

$$