Combine 2a^3+5a-7 and 5a^2-6a+12.
Rewrite this so that the second expression is beneath the first:
2a^3+5a-7
5a^2-6a+12
Combine like terms. The highest order term is 2a^3:
2a^3+0a^2 +5a-7
+5a^2 - 6a+12
----------------------------
2a^3 + 5a^2 - a + 5 (answer)
Note how these terms are in descending order by power of a.
