(1)8a+2b+5(a-b)
=8a+2b+5a-5b
=13a-3b
(2)6a-2(a-c)
=6a-2a+2c
=4a+2c
(3)-4(5a-3b)-3(a^2-2b)
=-20a+12b-3a²+6b
=-20a-3a²+18b
(4)2a-(5a-3b)+3(2a-b)
=4a-5a+3b+6a-3b
=5a
(5)(ax+by)-9(ay-bx)-7(-2ax+by+ay-3bx)
=ax+by-9ay+9bx+14ax-7by-7ay+21bx
=15ax-6by-16ay+30bx