Find an equation of the line in the form ax+by=​c, where​ a, b, and c are integers with no factor common to all three and a≥0.
The line with​ y-intercept 9 and perpendicular to x+7y=7
The equation of the line in the form ax+by=​c, with​ y-intercept 9 and perpendicular to x+7y=7 is ?