Question 254981
step 1 - solve the equation for y. We already have that as y=(8/7)x-9 
step 2 - identify the slope. m = (8/7)
step 3 - we want perpendicular slope so take our slope and negative flip it to get m = (-7/8).
step 4 - put this new slope, m = -7/8 and (8, -1) into y = mx + b and solve for b. We get
{{{y = mx + b}}}
{{{-1 = (-7/8)*8 + b}}}
{{{-6 = b}}}
step 5 - write the equation with your new m and b values as
{{{y = (-7/8)x - 6}}}