an apple cost 3x+6 pesos while an orange cost 4x-5 pesos. what is the total cost of 1 dozen apples and half dozen of orange

I suspect x is meant to be the number of items purchased here. That is:

cost of apples = 3*number of apples + 6 pesos.

cost of oranges = 4*number of oranges - 5 pesos

If that is the case then total cost = 3*12 + 6 + 4*6 - 5 = 61 pesos

$$1\ dozen = 12$$

$$1/2 \ dozen = 6$$

dozen(apples)

12(3x+6)

36x+72

1/2dozen(oranges)

6(4x-5)

24x-30

dozen apples + 1/2dozen oranges

(36x+72) + (24x-30)

(36x+24x) + (72-30)

60x + 42

So our answer is 60x + 42 pesos.

If we knew the value of x, we could find the exact cost. We don't though, so this is our final answer.

I suspect that Alan's interpretation might be correct, ND, but I read the problem just as you did. Therefore, I'm giving points to both answers.....it wasn't particularly clear what was meant, IMHO...