Question

Show that the points A(-1,7),B(1,2) andC(6,4) are the vertices of an isosceles right angled triangle

Answer 1

Here it is!
AB=BC
Hence its isosceles and when it satisfies the relation of pythagoras theorem i. e. AB^2+BC^2=AC^2.. Its an isosceles right angled triangle!!
Hope it helps!