Answer: 90 Earth years.
Step-by-step explanation:
Analizing the information provided in the exercise, you need to find the Least Common Multiple (LCM) of the given numbers.
You can follow these steps:
1. You must descompose 6, 9, 15 and 18 into their prime factors:

2. Finally, you need to choose the commons and non commons with their greatest exponents and multiply them. Then you get:

Therefore, it will take 90 Earth years for them to all line up.
Exact form: 169/28
decimal form: 6.03571428
mixed number form: 6 1/28
Answer:
A, C and E
Step-by-step explanation:
Simplify each expression to lowest terms. Equivalent expressions will be any expressions which are equal after simplifying to lowest terms.
A. -1/9 * 6 = -6/9 = -2/3
B. -15/10 = -3/2
C. 12/-18 = -2/3
D. -3/4 * 2/1 = -6/4 = -3/2
E. -8/9 * 3/4 = -24/36 = -2/3
The answer to the equation is b -16