Can I combine two objective functions if they have a relation between them?

Question

I will use a meta-heuristic algorithm, to maximize the following objective functions:

• Objective function 1 $=\sum\limits_{r=1}^{M} \sum\limits_{s=r+1}^{M} \sum\limits_{j=r+1}^{N} (r_{rj}w_j - r_{sj}w_j) $

• Objective function 2 $= \sum\limits_{j=r+1}^{N} [(2w_1r_{1j} ) + (0.5w_2r_{2j})+(1w_3r_{3j}) ] $

subject to:

• $ 0 \le w_1, w_2, w_3 \le 10$
• $ w_1+ w_2+ w_3 = 10$

Can I combine two objective functions if they have a relation between them? Or consider the problem as a multi-objective optimization problem?