Simplify.

(8m² + 3m – 6) - (9m-7) + (3m² – 2m + 4)

At the end of the year 2016, the population of villages Kovad, Varud, Chikhali is 5x² – 3y², 7y² + 2xy and 9x² + 4xy respectively. At the beginning of the year 2017, x² + xy – y²,5xy and 3x² + xy persons from each of the three villages respectively went to another village for education then what is the remaining total population of these three villages?

Polynomials bx² + x + 5 and bx³ – 2x + 5 are divided by polynomial x – 3 and the remainders are and respectively. If m – n =0 then find the value of b.

Which polynomial is to be subtracted from x² + 13x + 7 to get the polynomial 3x² + 5x – 4?

Which polynomial is to be added to 4m + 2n + 3 to get the polynomial 6m + 3n + 10?