I’m assuming the question is to find the equation of line.
Generally the equation of a line is in the form y=mx+c where m is the slope and c is the y-intercept. We know the slope is -9; so we have
y= -9x+c
Now substitute (6,7) in the equation to find c.
7=-9(6)+c
7=-54+c
c=7+54
c= 61
So equation of line is y = -9x+61