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
Step-by-step explanation:
Since X is given to you (in this case, it’s 7), all you have to do is plug it into the equation.
1. -2(7) + 10
When a variable or a number is directly outside a number, it means you should multiply the two numbers, no matter what.
Now that we know this: -2 * 7 = (-14) When a negative is multiplied by a positive, it turns out negative.
2. (-14) + 10: Let’s say (for instance), that I owe 14 dollars to a friend. If I pay 10 of it, how much do I owe my friend? It would be -4 because you’re still in debt, and haven’t payed your friend all of her 14 dollars back.
3. You should come up with an answer of (-4) because of all of the steps given.
If something doesn’t make sense, please make a note of it and tell me. Otherwise, have a splendid day.
Answer:
10
Step-by-step explanation:
on Ed
genuity it's right
Answer:
12:21
Step-by-step explanation:
4 + 7 = 11
33/11 = 3
3x4=12 & 3x7=21
Therefore, ratio is, 12:21
