Answer:

Step-by-step explanation:
The nth term of an arithmetic sequence is given by the formula,

We were given that the 9th term is
.





The sum of the first n-terms is given by the formula,

To find
, we substitute
,
and
.





The correct answer is D
Answer:
x =4
Step-by-step explanation:
x/y = 1/2
(x + 2) / (y + 1) = 2/3
Cross multiply the first equation
2x = y
Put that value for y into the second equation.
(x + 2) / (2x + 1) = 2/3 Cross multiply
3(x + 2) = 2(2x + 1) Remove the brackets.
3x + 6 = 4x + 2 Subtract 3x from both sides
6 = 4x - 3x + 2
6 = x + 2 Subtract 2 from both sides
6-2 = x
x = 4
We know we have $4.40 for 4. Divide 4.40 by 4, you get 1.10. So it's $1.10 per notebook. Therefore, divide 6.60 by 1.10. You get 6, so you can get six notebooks with $6.60.
Hope this helps!
Answer:
y=-2
Step-by-step explanation:
you are solving for the variable y
add 3 to the opposite side, so it cancels out
y=-5+3
y=-2