Answer:
David's score= 160 ; Aaron's score = 55
Step-by-step explanation:
let Aaron's score be 'x'.
so, David's score will be 3x - 5
(3x - 5) + x = 215
3x + x - 5 = 215
4x = 215 + 5
4x = 220
x = 220/4
x = 55
therefore, Aaron's score = 55
David's score is (3x - 5) = (3*55) - 5 = 165 - 5 = 160
Answer:
5)
1
Expand by distributing terms.
-2x-2\times 5−2x−2×5
2
Simplify 2\times 52×5 to 1010.
-2x-10−2x−10
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.
