Simple add them all 2+7+3+7+9 is 28 then divide 28 by the amount of numbers (5) to get 5.6 or if you are rounding to the nearest number 6... Hope this helped ;)
Answer: 
Step-by-step explanation:
GCF = Greatest common factor.
For example: 6 is the GCF of 12 and 18.
The given expression: 
It can be written as

Taking out common factor
, we get
![5y(x^2-6xy-7y^2)\\\\ =5y(x^2+xy-7xy-7y^2)\ \ [\because-6xy=xy-7xy]\\\\=5y(x(x+y)-7y(x+y))\\\\= 5y((x+y)(x-7y))\\\\=5y(x+y)(x-7y)](https://tex.z-dn.net/?f=5y%28x%5E2-6xy-7y%5E2%29%5C%5C%5C%5C%20%3D5y%28x%5E2%2Bxy-7xy-7y%5E2%29%5C%20%20%5C%20%5B%5Cbecause-6xy%3Dxy-7xy%5D%5C%5C%5C%5C%3D5y%28x%28x%2By%29-7y%28x%2By%29%29%5C%5C%5C%5C%3D%205y%28%28x%2By%29%28x-7y%29%29%5C%5C%5C%5C%3D5y%28x%2By%29%28x-7y%29)
Hence, 
1000 ml costs £3.50
200 is 1/5 of 1000 so it will be £0.7
To solve this, create an equation that follows 45% of a value is 18. This would look like x*.45=18. Now, solve for x, x*.45=18, divide by .45, x=18/.45=40, making your value 40. To check, plug in your value to the equation 40*.45=18 and see if it stays true.
The Mid-Atlantic Ridge. It's under the Pacific. Hope this helps!