1. Expand 20a(a + bc)
2. Expand 4a(3a + 6b)
3. Expand s2(2t + 3t2)
4. Expand 10st(s + t + u)
5. Expand 7c(2ab + 4c + 11)
6. Expand 15ac(1 + 2b + 3c)
7. Expand 2s2(3st + 4t + 11)
8. Expand 4s2(2st + 7s + 11)