Answer:
AC = 2x-19y
Explanation:
Given vector the following vector equations OA = 13x+7y , OB = 5x+12y and CO = -15x+12y, the following expression is true about vector OA, OB and OC;
OA+OB = CO (CO is the resultant since its is moving in the opposite direction compare to OA and OB)
Also BO+OA = BA and AO+OC = AC
If OB = 5x+12y, then BO = -(5x+12y)
BO = -5x-12y (BO = -OB)
Since BO+OA = BA
BA = -5x-12y + 13x+7y
BA = -5x+13x-12y+7y
BA = 8x-5y
Similarly AO+OC = AC
Since AO = -OA and OC = -CO
-OA-CO = AC
AC = -(13x+7y)-(-15x+12y)
AC = -13x-7y+15x-12y
AC = -13x+15x-7y-12y
AC = 2x-19y