9514 1404 393
Answer:
a9 = -8 +9(9 -1)
Step-by-step explanation:
The given sequence has a common difference of 1-(-8) = 10-1 = 9, and a first term of -8. The formula for the n-th term of such an arithmetic sequence is ...
an = a1 +d(n -1) . . . . . first term a1, common difference d
For the parameter of this sequence, a1=-8 and d=9, the n-th term is ...
an = -8 +9(n -1) . . . . formula for the n-th term
__
Then the formula for the 9th term is ...
a9 = -8 +9(9 -1)
3x + 6 + 4 = 6 × 2 + 10
3x + 6 + 4 = 12 + 10
3x + 10 = 12 + 10
3x + 10 = 22
3x = 22 - 10
3x = 12
x = 12/3
x = 4
The answer is: x = 4.
