Question

(13a+6b)+(5a-4b)-(-3a+6b)

Answer 1

13a +6b+5a-4b+3a-6b =
separate both a and b.
13a+5a+3a+6b-4b- 6b=
21a-4b=0

Answer 2

Hi ,

( 13a + 6b )+( 5a - 4b ) - ( -3a + 6b )

= 13a + 6b + 5a - 4b + 3a - 6b

Arrange like terms at one place

= 13a + 5a +3a +6b - 4b - 6b

= ( 13 + 5 + 3 )a + ( 6 - 4 - 6 )b

= 21a - 4b

I hope this helps you.

:)