ANSWER:

1.) (x+3y)+(4x-6y)

=x+3y+4x-6y

=5x-3y

2.) (2a-3b)+(a+5b)+(-5a-7b)

=2a-3b+a+5b-5a-7b

=-2a-5b

3.)(6x-2y+2z)+(x-4y+5z)+(3y-z)

=6x-2y+2z+x-4y+5x+3y+z

=7x-3y+6z

4.) (6x+y)+(4x-4y+3z)+(2x-3y+5z)

=6x+y+4x-4y+3z+2x-3y+5z

=12x-6y+8z

Or

(6x+y)+(4x-4y+3z)+(2x-3y+5z)

=6x+y+4x-4y+3z+2x-3y+5z

=12x-6y+8z

=2(6x-3y+4z)

5.) (a-b+3c)+(2a-5b+c)+(-3a+6b-4c)

=a-b+3c+2a-5b+c-3a+6b-4c

=0+0+0

=0

Step-by-step explanation:

HOPE IT HELP^_^