Show that the given lines are the legs of a right triangle?

"Show that the lines 6x + 7y - 6 = 0 and 7x - 6y + 9 = 0 are the legs of the right triangle." Thank you.

6x+7y-6=0
7y=-6x+6
y=(-6/7)x+6/7
m1=-6/7
7x-6y+9=0
-6y=-7x-9
y=(7/6)x+9/6
m2=7/6
m1=-1/m2
the two lines are perpendicular to each other
so the could be the legs of a right triangle

Their slopes (-7/6 & 6/7) multiply to yield -1.

Since the product of slopes is -1 view that they may be the legs of a right angled triangle.