1. Distribute
7i × 5 + 7i × -9i
2. Simplify 7i × 5 to 35i
35i + 7i × -9i
3. Simplify 7i × -9i to -63ii
35i - 63ii
4. Use the Product Rule
35i - 63i^2
5. Use the Square Rule
35i - 63 × -1
6. Simplify 63 × -1 to -63
35i - (-63)
7. Simplify brackets
35i + 63
8. Regroup terms
63 + 35i