Respuesta :

The standard form is Ax + By = C
with A being both positive and non-fraction

so we are given 3x - 9 = 7y
we add the 9 to both sides
3x = 7y + 9 
and subtract the 7y from both sides
3x - 7y = 9

There you have it in standard form

Hope this helps ;)
bcalle
Ax + By = C is standard form
3x - 7y = 9