Hello from MrBillDoesMath!
Answer:
n = 5
Discussion:
Let the original number be "n" Translating the problem statement to mathematical symbolism:
n + 4 = 19 - 2n => add 2n to both sides
n + 2n + 4 = 19 - 2n + 2n => combine like terms
3n + 4 = 19 => subtract 4 from both sides
3n = 19 -4 = 15 => divide both sides by 3
n = 15/3 =5
Check: Does 5 +4 = 19 - 2(5)? Does 9 = 9? Yes. so the value for n is confirmed correct.
Thank you,
MrB
Answer:

Step-by-step explanation:
Given : Vertices of Triangle
,
and 
To find : Centroid of a triangle
The centroid of a triangle is the point of intersection of the three medians of the triangle.
The formula to calculate the centroid of a triangle is:

Where,
are the coordinates of the centroid
Substituting the values in the formula gives us:



Therefore, 
Answer:
90
Step-by-step explanation:
30x3=90
Answer: In set theory, the union (denoted by ∪) of a collection of sets is the set of all elements in the collection. It is one of the fundamental operations through which sets can be combined and related to each other.
A U B U C = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }
Step-by-step explanation:
A = {1, 2, 5, 7}
B = {3, 4, 6, 7}
C = {0, 5, 8, 9}
A U B U C = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }