Answer:
x2 − 14x + 49 = 0
Step-by-step explanation:
17 tens can be said as 17 x 10
So 17 x 10 is 170
170 is in standard form
Because 17 - 14 = 14 - 11 = 3, the ratio of the arithmetic series is 3;
Then, A4 = 8 - 3 = 5; A3 = 5 - 3 = 2; A2 = 2 - 3 = -1; A1 = -1 - 3 = -4.
But 68 = A1 + ( n- 1 ) x r;
68 = -4 + ( n - 1) x 3;
( n - 1 ) x 3 = 72;
n - 1 = 24;
n = 25;
Finally, Sn = ( A1 + An) x n / 2; then, S25 = ( - 4 + 68) x 25/2;
S25 = 64 x 25 / 2;
S25 = 32 x 25;
S25 = 800;
The value of sum is 800.
R = 3
6x3=18
18x3=54
54x3=162 ...
