5. Given the line $a x+b y+c=0$ where $a, b, c$ are 3 different elements taken from the set $\{-3,-2,-1,0,1,2,3\}$, and the inclination angle of the line is acute, then the number of such lines is $\qquad$

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43
5.【Analysis and Solution】Let the inclination angle be $\theta$, then $\tan \theta=-\frac{a}{b}>0$, assume $a>0, \therefore b<0$.
(1) $c=0, a$ has three choices, $b$ has three choices, excluding 2 duplicates $(3 x-3 y=0,2 x-2 y=0$ and $x-y=0$ are the same line), so there are $3 \times 3-2=7$ (lines);
(2) $c \neq 0$, then $a$ has three choices, $b$ has three choices, $c$ has 4 choices, and any two lines among them are different, so there are $3 \times 3 \times 4=36$ (lines),
$\therefore$ the number of lines that meet the requirements is $7+36=43$ (lines).