Distribute sum groups
a(2a^2 - 5a - 2) - 2(2a^2 - 5a - 2)
Expand
2a^3 - 5a^2 - 2a - (4a^2 - 10a - 4)
Simplify brackets
2a^3 - 5a^2 - 2a - 4a^2 + 10a + 4
Collect like terms
2a^3 + (-5a^2 - 4a^2) + (- 2a + 10a) + 4
Simplify
= 2a^3 - 9a^2 + 8a + 4
