(3a³ - 5b³) + ? a³+ ? b³ =(a³+b³)

Answer:
[tex]\boxed{-2; 6}[/tex]
Step-by-step explanation:
Think of this as an ordinary addition problem.
What must you add to 3a³ to get 1a³? Answer: add -2a³
3 + (-2) = 1
What must you add to -5b³ to get 1b³? Answer: add 6b³
-5 + 6 = 1
Then, the addition looks like this:
[tex]\begin{array}{rcr}3a^{3} & + & -5b^{3}\\\boxed{-2}a^{3} & + & \boxed{6}b^{3}\\a^{3} & + & b^{3\\\end{array}[/tex]
The numbers in the boxes are -2 and 6.