Answer:
A: an = 6n - 9
Step-by-step explanation:
third term in an arithmetic sequence is 9
a3 = a + 2d
a + 2d = 9
the fifth term is 21
a5 = a + 4d
a + 4d = 21
a + 2d = 9 (1)
a + 4d = 21 (2)
Subtract (1) from (2) to eliminate a
4d - 2d = 21 - 9
2d = 12
d = 12/2
d = 6
Substitute d = 6 into (1)
a + 2d = 9 (1)
a + 2(6) = 9
a + 12 = 9
a = 9 - 12
a = -3
nth term of this sequence = a + (n - 1)d
= -3 + (n - 1)6
= -3 + 6n - 6
= 6n - 9
an = 6n - 9
Answer:
36 Teachers in Total
Step-by-step explanation:
I would use Ratio.
Students: 128 + 121 + 135 = 384 total students
Teachers: Students
3 : 32
36 : 384
384 ÷ 32 = 12
12 x 3 = 36
The answer is A because we dont know how many baseball cards blake had so you would add .25 to b
