ANSWER
C) 1, 3, 6, 10, 15, 21, 28, 36, 45
EXPLANATION
The recursive formula is,

when n is a natural number greater than 1.
When n=2,


when n=3,

when t=4,

When t=5,

when t=6,.

when t=7

When t=8,

When t=9,

Hence the first nine triangular number are
C) 1, 3, 6, 10, 15, 21, 28, 36, 45
Answer:
25
Step-by-step explanation:
The other factor would be (x + 4). We can find this by using synthetic division. To do this, we must first find the divisor, which would be 9, if we let x - 9 equal to zero and solve for x. Then, for the dividend, we can use the coefficients and constant term values.
<u>9</u>| 1 -5 -36
<u> 9 36</u>
1 4 0
Therefore, the other expression (x + 9) would be (x + 4). Hope this helped!
If x + y = 6, then solve for y to get: y = 6 - x.
Now replace y with 6 - x in both equations.
(5x)/3 + 6 - x = c
2(6 - x) = c - 4x
The upper equation is solved for c.
Now we solve the lower equation for c.
c = 2(6 - x) + 4x
c = 12 - 2x + 4x
c = 2x + 12
Since we have two equations solved for c, we substitute to get
(5x)/3 + 6 - x = 2x + 12
This is an equation in only x, so we can solve for x.
(5x)/3 - 3x = 6
5x - 9x = 18
-4x = 18
x = -9/2
Now we solve for y.
x + y = 6
-9/2 + y = 6
y = 9/2 + 12/2
y = 21/2
Now we solve for c.
c = (5x)/3 + y
c = (5 * (-9/2))/3 + 21/2
c = -45/6 + 21/2
c = -15/2 + 21/2
c = 6/2
c = 3
Answer: c = 3