Ответ:\(-9a+5y-3y-6a=-15a+2y\).\(10a-15d+11c-12a-25d=-2a+11c-40d\).\(-8-c+3a-6c+3-a=2a-7c-5\).\(5.3a-4c+1.8a+5-3c=7.1a-7c+5\).