Answer :
1) 8v+w+7-8v+2w
=w+7+2w
=3w+7
-----------------------------
2) 4c^2+6c-3c^2-2c-3
=c^2+6c-2c-3
=c^2+4c-3
-------------------------------
3) z^3+5z+3z^2+1-4-2z^2
=z^3+z^2+5z+1-4
=z^3+z^2+5z-3
=w+7+2w
=3w+7
-----------------------------
2) 4c^2+6c-3c^2-2c-3
=c^2+6c-2c-3
=c^2+4c-3
-------------------------------
3) z^3+5z+3z^2+1-4-2z^2
=z^3+z^2+5z+1-4
=z^3+z^2+5z-3