3.
consecutive odd numbers starting at
1 are added together. their sum is
400. how many numbers were
added?

20

Step-by-step explanation:

Sn = (n/2)(a1 + a1 + d(n-1)), where S = sum, a1 = first term, n = number of terms, d = common difference

400 = (n/2)(1 + 1 + 2(n - 1))

400 = (n/2)(2  + 2n - 2)

400 = (n/2)(2n

400 = n2

20 = n

Twenty numbers are in the set.

your answer is 23/2 - 13.5

step-by-step explanation:

7/2 evaluates to

multiply x and 4.5

multiply x and 1

the x just gets copied along.

the answer is x

x

4.5*x evaluates to 4.5x

multiply 3 and 4.5x

multiply 1 and x

the x just gets copied along.

x

4.5*x*3 evaluates to 13.5x

7/2-4.5*x*3 evaluates to

  + 8 =

the answer is

7/2-4.5*x*3+8 evaluates to

i believe the answer is the polygon, heptagon.