Answer:
21
Step-by-step explanation:
Given AC = 23, AB = 2x + 2 and BC = 3x+6 then using vector notation;
BA+AC = BC
Since BA = -AB
The equation becomes -AB+AC = BC
Substituting the given equations;
-(2x+2)+23 = 3x+6
open the parenthesis
-2x-2+23 = 3x+6
-2x+21 = 3x+6
collect the like terms
-2x-3x = 6 - 21
-5x = -15
Divide both sides by -5
-5x/-5 = -15/-5
x = 3
TO get BC, we will substitute x = 3 into the expression BC = 3x+6
BC = 3(5)+6
BC = 15+6
BC = 21
Hence the length of BC is 21 units
