Answer:2 5/6
Step-by-step explanation:
i used photomath :)
It is asking you to find the sum of k^2 - 1 from k=1 to k=4. Since that is only 4 numbers, calculating the sum by hand wouldn’t be that bad.
(1^2 - 1) + (2^2 - 1) + (3^2 - 1) + (4^2 - 1) = 26
The easier way to find the sum is to use a few simple formulas.
When we have a term that is just a constant c, the formula is c*n.
When we have a variable k, the formula is k*n*(n+1)/2.
When we have a squared variable, the formula is k*n*(n+1)*(2n+1)/6.
In this case, we have a squared variable k^2 and a constant of -1.
So plug in n=4 to the formulas:
4*5*9/6 - 1*4 = 26
The answer is 26
Answer:
6x^2 - 10x - 24
Step-by-step explanation:
- Do 3x times 2x which is 6x^2
- Do 3x times - 6 which is -18x
- Do 4 times 2x which is 8x
- Do 4 times - 6 which is - 24
- You get 6x^2 - 18x + 8x - 24
- Simplyify to get the answer
Answer:
The area of the 3d figure
Step-by-step explanation:
the area of the one of triangle is 8.7
and the reactangle is 5 x 7 = 35
and the big one is 10 x 7 = 70
so 8.7 + 8.7 + 35 + 35 + 70 = 157.4
