1) 4*(5a-3b+c)-3*(2a-b-3c) = 20а–12b+4c–6a+3b+9c= 14а-9b+13c
2) (x-y)-(y-z)-(z+x) =x-y-y+z-z-x=-2y
3) 2a*(3b-5c)-3c*(-3a+2b)+4b*(6a-2c) = 6ab-10ac+9ac-6cb+24ab-8bc = 30ab-ac-14bc
1) 4*(5a-3b+c)-3*(2a-b-3c) = 20а–12b+4c–6a+3b+9c= 14а-9b+13c
2) (x-y)-(y-z)-(z+x) =x-y-y+z-z-x=-2y
3) 2a*(3b-5c)-3c*(-3a+2b)+4b*(6a-2c) = 6ab-10ac+9ac-6cb+24ab-8bc = 30ab-ac-14bc