Answer:
4x +3y = -3
Explanation:
The standard form equation can be written from ...
(y2 -y1)x -(x2 -x1)y = (y2 -y1)x1 -(x2 -x1)y1
(-13 -3)x -(9 -(-3))y = (-16)(-3) -(12)(3)
-16x -12y = 12
The standard form has a positive leading coefficient, and all terms mutually prime. We can get that by dividing the equation by -4:
4x +3y = -3
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Additional comment
The form we used above for the equation of the line essentially comes from the fact that the slope of a line is the same everywhere:
(y2 -y1)/(x2 -x1) = (y -y1)/(x -x1)
Multiplying by the product of denominators and separating variable terms from constant terms gives the form used above.