Mathematical models are helpful. Advantages include helping you see the data clearer and helping you visualize. Disadvantages are: time consuming, and if you make a mistake on the graph, its going to hit the entre thing.

Step-by-step explanation:
d=20
r=10
π=3



-6x=19+17
-6x=36 /(-6)
x=-6
Given:
The inequality is:

To find:
The y-intercept, slope and type of line (solid or dotted).
Solution:
The slope intercept form of a line is:
...(i)
Where, m is the slope and b is the y-intercept.
We have,

The relation equation is:
...(ii)
On comparing (i) and (ii), we get


It means the slope is 5 and the y-intercept is 3.
The sign of the inequality in the given inequality is ">". It means the boundary line is not included in the solution set. So, the boundary line is a dotted line.
Therefore, the slope is 5, the y-intercept is 3 and the line is a dotted line.
Answer:
Part a) The measure of the sides of triangle DEF are



Part b) Is a scalene triangle
Step-by-step explanation:
we know that
the formula to calculate the distance between two points is equal to

we have the coordinates
D(8,-6) E(-1,-3) F(-2,5)
step 1
Find the length side DE
D(8,-6) E(-1,-3)
substitute in the formula



step 2
Find the length side EF
E(-1,-3) F(-2,5)
substitute in the formula



step 3
Find the length side DF
D(8,-6) F(-2,5)
substitute in the formula



step 4
Classify the triangle by the measure of its sides
we have



so
Is a scalene triangle, because is a triangle in which all three sides have different lengths.