x is the variable
<em>In mathematics, a variable is a symbol; in this case, X.</em>
Answer:

Step-by-step explanation:
You would start by writing the expression for “subtract 3 from 15", which would be
, then you would add on "then divided by 6", which would make it
Answer:
n=-1
Step-by-step explanation:
First you add 5 to both sides an you would get -15n=15
Next divide by -15 on both sides and get n=-1
Answer:
300 dollars
Step-by-step explanation:
Let the original amount = x
x - 2/5x was what his mother's share looked.
5/5 x - 2/5 x
3/5x is what is left.
3/5 x - 1/4 * 3/5 x - 2/3x * 3/5 = his sister's share and his brothers
3/5x - 1/4*3/5 x - 2/3 * 3/5 = 15
3/5x * (1 - 1/4 - 2/3) = 15
3/5 x 5/60 = 15
15 / 300 * x = 15
1/20 x = 15
x = 15 * 20
x = 300
A)
Since 5 of the books are new, that means that the other books are used. So, there are 11-5=6. The ratio would be 5:6.
b)
The ratio is 6:11. You get the 6 from the above problem.
Hope this helps!