B. Find the sum of the following polynomials.
1. 10mn and -15mn ____________________________________________

2. -7a

2

and -8a

2

____________________________________________

3. 6(x+3) and -7(x+3) ____________________________________________

4.

1

4

ab and -

1

4

ab ____________________________________________

5. 0.5 xyz and 1.5 xyz ____________________________________________​