Question 4 Consider the group presentation (a,b,cla²bc², a¹bc¯¹, aba¯¹b¯¹). Show that, modulo the relations, we have ba²cb1abc² = e. Show all steps. (Hint: Try inserting a¹bc¹ between some letters and see how this goes. Also, note that the relation aba¯¹b-¹ tells us that ab = ba, it can be very useful!)