Answer:
BC= 20 units
Step-by-step explanation:
Since ∆ ABC is an equilateral triangle, all the sides are equal in length.
AC= BC
=>-y+23= 6y+2
=>-y-6y= 2-23
=>-7y= -21
=>y= 21/7
=>y= 3
BC = 6y+2 = 6(3)+2 = 18+2 = 20 units
