Question

Add the following polynomials, then place the answer in the proper location on the grid. Write the answer in descending powers of a. Add: 2a3 + 5a - 7 and 5a2 - 6a + 12

Answer 1

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.