Question

What must be added to 2a³ + 5a – a² – 6 to get a² – a – a³ + 1?

Answer 1

We get, the required result by subtracting

2a³ + 5a – a² – 6 from - a³ + a² - a + 1 

= (- a³ + a² - a + 1) - (2a³  – a² + 5a – 6)

= - a³ + a² - a + 1 - 2a³  + a² - 5a + 6

= - a³  - 2a³ + a² + a² - a - 5a + 1 + 6

= - 3a³ + 2a² - 6a + 7