Answer:
1. 3x+15
2. 4x+36
3. 4x+36
4. 6x-2
5. 5x-10
6. 4x-24
7. 2x+1
8. 6x+21
9. 4x+16
10. 4x+10
11. x+4
12. 5x-10
To expand an equation, you can apply the distributive property
==> The distributive property, sometimes known as the distributive property of multiplication, tells us how to solve certain algebraic expressions that include both multiplication and addition.
CREDIT: prepscholar.com ^ for the definition of the distributive property