Answer:

Step-by-step explanation:
Addition/subtraction of fractions requires that they share a common denominator...
By inspection, LMNO is similar to PQRS.
For similar figures, corresponding sides are proportional, therefore
LM/PQ=MN/QR
Substituting values
4/2=6/c
Cross-multiply
4c=6*2=12
c=12/4=3
Answer:
Elizabeth washes 99 windows each day.
Step-by-step explanation:
Given:
Total number of windows (N) = 2480
Marie washes windows = 4 times Elizabeth washes.
Elizabeth washes same number of windows for 5 days.
Let the number of windows washed by Elizabeth each day = 'x'.
Therefore, over the 5 days, the windows washed by Elizabeth = 
Now, as per question:
Marie washes windows = 4 times Elizabeth washes.
So, number of windows washed by Marie = 
Now, total number of windows = Windows washed by Marie + Windows washed by Elizabeth
So,

Therefore, Elizabeth washes 99 windows each day.
It's very important to use the symbol " ^ " here to denote exponentiation.
You probably meant "-10x^(-10), which would be "-10 times x to the minus tenth power."
If you want the value, you could do the following:
-10 1
------------------ = - ---------- = - 10^(-9).
10^10 10^9