Identify the terms, their co-efficients for each of the following expressions:
(i) 7x2yz−5xy (ii) x2+x+1 (iii) 3x2y2−5x2y2z2+z2
(iv) 9−ab+bc−ca (v) a2+b2−ab (vi) 0.2x−0.3xy+0.5y