Slope = (y2 - y1) / (x2 - x1)
(10,2)...x1 = 10 and y1 = 2
(3,5)...x2 = 3 and y2 = 5
now we sub
slope = (5 - 2) / (3 - 10) = 3/-7 = -3/7 <==
Elimination is used when there is a common factor between the two equations. Substitution is used in cases where finding a common term just isn’t possible, or too complicated.
I would just use A^2 plus B^2 to get it, but I would ignore the length off the floor because it doesn't change the actual length of it