First, did you mean 4y - 6x = 15?
The answer is “c” 0 Bc that is the only thing that makes sense
Answer:

Step-by-step explanation:
we know that
In an <u><em>Arithmetic Sequence</em></u> the difference between one term and the next is a constant, called the common difference
The formula for an Arithmetic Sequence is equal to

where
d is the common difference
n is the number of terms
a_1 is the first term of the sequence
In this problem we have

substitute



so
<u><em>Find the first ten terms</em></u>

For n=2 ----> 
For n=3 ----> 
For n=4 ----> 
For n=5 ----> 
For n=6 ----> 
For n=7 ----> 
For n=8 ----> 
For n=9 ----> 
For n=10 ----> 
The sequence is

Gabrielle's age is 3x (in which x is mikhail's age)
the sum is 56 so 3x+x=56
3x+x=56
4x=56
x=14
since x was mikhail's age, mikhail is 14 years old