Umm I don't understand this...Can someone explain it...I will mark the one who make it a little clear to me..

12

Step-by-step explanation:

step 1 take z.y+x-b+a-o

step 2 lets say that Z=3 Y=2 X=4  B=6  A=9  O=1

step 3 write out the  problem 3.2=6+4=10-6=4+9=13-1=12

step 4 when you get this done and you have the same answer as mine show your teacher that you are done just take what i typed for the problem.