"The intersection (∩) of a pair of sets (G and H) is a third set (I) composed by the elements that belong, at the same time, to both given sets."
According to this definition:
Given the sets:
G = {3, 7, 8, 9}
H = {2, 5, 7, 8}
The Intersection is:
G ∩ H = I = {7, 8}
:-)
Answer:

Step-by-step explanation:
We are given that Ben has a cell phone plan that provides 200 free minutes each month for a flat rate of $39.
We are also told that For any minutes over 200, Ben is charged $0.35 per minute.
let x be the minutes used each month
So, if 
So, coat will be $39
If 
So, Ben is charged $0.35 per minute
So, when 
So, charge = 
So, the piecewise functions accurately represents charges based on Ben's cell phone :

<span>Given the two end of the diameter of the circle, we are able to compute the center of the circle as 0.5*[(-1,3)+(7,-7)]=(3,-2). The radius of the circle is 0.5*sqrt[(-1-7)^2+(3+7)^2]=sqrt(41). Therefore the equation of the circle is (x-3)^2+(y+2)^2=41.</span>
Answer: The correct option is D, i.e.,30.
Explanation:
It the given equation we have two units l and dl.
Where l represents the liter and dl represents the deciliter. These are the volume units.
We know that,
1 liter = 10 deciliter
It means,
1 l = 10 dl
Multiply both sides by 3,
1\times 3 l = 10\times 3 dl
3 l = 30 dl
Therefore, the correct option is D and 3 l = 30 dl.