Answer:
15
Step-by-step explanation:
If this is an arithmetic progression, then there is a common difference.
-3-18 = -21
-21/3 = -7
18 - 7 = x
x = 11
11 - 7 = y
y = 4
4 - 7 = -3
x + y
11 + 4 = 15
Hello,
to find the total cost (c) of the colored strips we have to multiply the number of strips (n) by the cost of each color strip (99¢), that as an algebraic function is:

[¢]
Now, if we use 3 solid color strips, that means that we use 4 patterned strips, so:
Answer: c=n*99 and Cost per curtain= $7.97
None, a triangle need to have angles measuring 180 degrees , its only possible if the triangle has three angles equaling 60
Would it be 9 because 8 times 3 equals 24 and 3 times 3 equals 9