In the general form, Ax+By+C=0, A is the coefficient of x, B is the coefficient of y, and C is the constant.
In the k form, y = kx + m, k is the coefficient of x, and m is the constant. y will always have a coefficient of 1 is this form.
Taking the k form, you can move the y term to the other side with kx and m to get general form:
Code
y = kx + m
-y = -y
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0 = kx - y + m
Since y is now negative, it is understood to now have a -1 coefficient, while x still have a coefficient of k, and the constant m.