Here you go :) Hope I can help
Answer:
- S7 = 175
- S17 = 2465
- Sn = 1/2(n³ +n)
Step-by-step explanation:
The progression of sums is ...
1, 5, 15, 34, 65, ...
So, first differences are ...
4, 10, 19, 31
Second differences are ...
6, 9, 12, ...
Third differences are constant:
3, 3, ...
This means the expression for Sn will be a cubic expression. If dn is the first of the n-th differences, then the equation can be written as ...
Sn = S1 +(n -1)(d1 +(n -2)/2(d2 +(n -3)/3(d3)))
And this simplifies a little bit to ...
Sn = 1 +(n -1)(4 +(n -2)(n +3)/2)
In simpler form, we have ...
Sn = 1/2(n³ +n)
Then the two terms we're interested in are ...
S7 = (1/2)(7³ +7) = 175
S17 = (1/2)(17³ +17) = 2465
<h2>
Answer</h2>
The equation is y = 2x - 12
<h2>
Explanation</h2>
Equation in slope intercept form is
Where,
m = slope
b = y-intercept
Putting the value of slope in this equation:
From this we can solve the equation for b
Now, the equation of y-intercept becomes
The answer is 15 inches. If you let h stand for the height. Set them equal. 1.25 = 15. divide both sides by 1.25. h = 12
Answer:
inequality: difference in size, degree, circumstances, etc.; lack of equality.
Step-by-step explanation:
