Subtract: (i) 4ab + 3b + 12 from 12ab + 5b (ii) 3xy + 5yz + xz from 5xy + 6yz + 6xz + 10xyz (iii) 4p²q + 7pq + 5pq² + 7q from 18p²q + 5pq + 6pq² + 5p²q

i) 12ab + 5b – (4ab + 3b + 12) = 12ab + 5b – 4ab – 3b – 12 = 8ab + 2b – 12

ii) 5xy + 6yz + 6xz + 10xyz – (3xy + 5yz + xz) = 5xy + 6yz + 6xz + 10xyz – 3xy – 5yz – xz = 2xy + yz + 5xz + 10xyz

iii) 18p²q + 5pq + 6pq² + 5p²q – (4p²q + 7pq + 5pq² + 7q) = 18p²q + 5pq + 6pq² + 5p²q – 4p²q – 7pq – 5pq² – 7q = 19p²q – 2pq + pq² – 7q