Question

Find the value of BC.

Answer 1

Well, since it's an equilateral triangle (as shown by the lines on each side), all sides must be the same... So technically BC = 1/2 x -2 AND 3/2 x - 12

But if you need a numerical value, you can make
1/2 x - 2 = 3/2 x - 12
Rearrange: -2 + 12 = 3/2 x - 1/2 x
= 10 = 2/2x
x = 10
Substitute back in:
1/2 * 10 - 2
= 5 - 2
= 3.
(To check if it is correct you can sub in 10 for x in the other equation and see if it gives the same answer)