Step-by-step explanation:

Answer:
3. SinD= 12/15; Sin E= 9/15
4. sinD= 35/37; sinE= 12/37
5. sinD= 28/53; sinE= 45/53
6. Because the numerator should be 12 since that is the side opposite to the angle A.
Step-by-step explanation:
I believe the equation shown above is an example of:
B. Associative Property of Addition.
Hope I helped!!
5x - 9 = -30
"Nine less than" means - 9
"Five times a number" means 5*unknown number = 5x