3. Given the line $a x+b y+c=0$, where $a, b, c$ are three distinct elements taken from the set $\{-3,-2,-1,0,1,2,3\}$, and assuming the line has an acute angle of inclination, the number of such lines is $\qquad$ .
3. Let the inclination angle be $\theta$, then $\tan \theta=-\frac{a}{b}>0$. By the symmetry of the sets of values for $a$ and $b$, without loss of generality, we can assume $a>0, b<0$. (1) When $c=0$, $a$ has $C_{3}^{1}$ ways to be chosen, $b$ has $C_{3}^{1}$ ways to be chosen, excluding 2 duplicates (since $x-y=0, 2x-2y=0, 3x-3y=0$ represent the same line), hence there are $C_{3}^{1} C_{3}^{1}-2=7$ such lines. (2) When $c \neq 0$, $a$ has $C_{3}^{1}$ ways to be chosen, $b$ has $C_{3}^{1}$ ways to be chosen, and $c$ has $C_{4}^{1}$ ways to be chosen, so there are $C_{3}^{1} C_{3}^{1} C_{4}^{1}=36$ such lines. Therefore, the total number of lines that meet the conditions is $7+36=43$.