20u2 – 28u 15x + 12y – 60
25a – 30ab + 15ab2
x 2 + xy + xz + yz
21ax + 35ay + 20y + 12x
152x 2 yz + 114xyz 2
30m2 n2 + 75mn2 – 105mn3
28pq2 r – 21p2 qr 2 + 14p3 qr + 7pqr k). 24abc – 30abd – 18b2 c + 36b2 d
ab + ab2 c 2 – ab + ab2 c
17m6 n6 – 51m4 n4 + 85m2 n2}