Y = |x - 21| represents an absolute value function.
Every square is a rectangle because it is a quadrilateral with all four right angle (a rectangle is not a square)
It's because most of them are the same measurements therefore are the same angles. 1 is just the name of the triangle and is based off their sides and measurements
It is the first option "y - 4 = 2/5 (x+2)".
Ordered pair (-2,4) is on the line.