Given:
Cost of 1 digital song = $1.05
Cost of 2 digital song = $2.10
Cost of 5 digital song = $5.25
To find:
The equation and the cost of 25 downloaded digital songs.
Solution:
Let us take two points (1, 1.05) and (2, 2.10).
Here 
Slope:


m = 1.05
Using point-slope formula:



Add 1.05 on both sides, we get

Here x is the independent variable and c is the dependent variable.
So that substitute x = n and y = c.

The equation is c = 1.05 n.
Substitute n = 25 in the equation.


The cost of 25 songs is $26.25.
Top left and bottom left are correct, the other two are not x
468.
Triangles=108
Base=120
Back=90
Front=150
X = 3; B = 70
60 + 15x + 5 + 22x + 4 = 180
69° + 37x = 180
37x = 180° - 69°
37x = 111°
x = 111/37
x = 3
B = 22x + 4
B = 22(3) + 4
B = 66 + 4
B = 70