Question

subtract 2a - 8a ^2 from 3a ^ 2 - 5a + 7​

Answer 1

Sum of 3a2 – 2a + 5 and a2 – 5a – 7

= 3a2 – 2a + 5 + a2 – 5a – 7

= 3a2 + a2 – 2a – 5a + 5 – 7

= 4a2 – 7a – 2

And sum of 5a2 – 9a + 3 and 2a – a2 - 1

= 5a2 – 9a + 3 + 2a – a2 – 1

= 5a2 – a2 – 9a + 2a + 3 – 1

= 4a2 – 7a + 2

Now, (4a2 – 7a + 2) – (4a2 – 7a – 2)

= 4a2 – 7a + 2 – 4a2 + 7a + 2

= 4a2 – 4a2 – 7a + 7a + 2 + 2

= 0 + 0 + 4 = 4

Answer 2

(3a² - 5a + 7) - (2a - 8a²)

=> 3a² - 5a + 7 - 2a + 8a²

=> 3a² + 8a² - 5a - 2a + 7

=> 11a² - 7a + 7 .........(ans)