If x+y+z=13 what is the value of (x-1) + (y+1) + (z-1)

12

Step-by-step explanation:

(x-1) + (y+1) + (z-1)

= x - 1 + y + 1 + z - 1

= x + y + z - 1

= (x + y + z) - 1

given that x+y+z = 13, substitute this value into the equation aove

(x + y + z) - 1

= 13 - 1

= 12