9x - y = - 7
the equation of a line in standard form is
Ax + By = C ( A is a positive integer and B, C are integers )
rearrange y = 9x + 7 into this form ( subtract y from both sides )
0 = 9x - y + 7 ( subtract 7 from both sides )
9x - y = - 7 ← in standard form
