Suppose $f(x) = x^2 + 4x - 6$ and $a = 0$.
Using $h = \pm 0.1, \pm 0.01$, approximate the limit of the difference quotient $\lim_{h \to 0} \frac{f(a + h) - f(a)}{h}$.
Suggestion: you may find it easier to first simiplify algebraically, and then put in the different values for $h$.
When $h = 0.1$, $\frac{f(a+h)-f(a)}{h} = \boxed{}
When $h = 0.01$, $\frac{f(a+h)-f(a)}{h} = \boxed{}
When $h = -0.1$, $\frac{f(a+h)-f(a)}{h} = \boxed{}
When $h = -0.01$, $\frac{f(a+h)-f(a)}{h} = \boxed{}$
