You can solve the equation for y:
y = (12 - 4x)/-3 = (4/3)x - 4
And for x:
x = (12 + 3y)/4 = (3/4)y + 3
Now for ...
x=0, y = (4/3)·0 -4 = -4
y=0, x = (3/4)·0 +3 = 3
x=9, y = (4/3)·9 -4 = 12-4 = 8
y=-8, x = (3/4)·(-8) +3 = -6 +3 = -3
[tex]\begin{array}{c|c}x&y\\0&-4\\3&0\\9&8\\-3&-8\end{array}[/tex]
