Triangular sequence = n(n + 1)/2
If 630 is a triangular number, then:
n(n + 1)/2 = 630
Then n should be a positive whole number if 630 is a triangular number.
n(n + 1)/2 = 630
n(n + 1) = 2*630
n(n + 1) = 1260
n² + n = 1260
n² + n - 1260 = 0
By trial an error note that 1260 = 35 * 36
n² + n - 1260 = 0
Replace n with 36n - 35n
n² + 36n - 35n - 1260 = 0
n(n + 36) - 35(n + 36) = 0
(n + 36)(n - 35) = 0
n + 36 = 0 or n - 35 = 0
n = 0 - 36, or n = 0 + 35
n = -36, or 35
n can not be negative.
n = 35 is valid.
Since n is a positive whole number, that means 630 is a triangular number.
So the answer is True.
Answer:
1
Step-by-step explanation:
7 + 2x = 9
Carry over the 7 to the 9.
2x = 9-7
2x= 2
x = 2÷2
x = 1
Answer:
Step-by-step explanation:
11904762\42 =283,446.7 houses per hour
For 121212 guests we need 555 liters,for 363636 guests how many liters
Guests Soda
121212 555
363636 x
So 121212*x=363636*555
x=363636*555/121212
x=555*3
x=1665
Answer:
7t
Step-by-step explanation:
