Question 681449
y=x-7 and (0,-5)

y=x-7

compare with the equation y = mx+b

m=1

so the slope is 1

the slope of line perpendicular to this line will be -1  (negative reciprocal)

using the equation
y-y1=m(x-x1) where m is the slope and (x1,y1) are the co ordibnates of the point on the line.

y-(-5)=-1(x-0)
y+5=-x
y=-x-5 is the equation