Answer:
Step-by-step explanation:
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Good evening ,
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2(7) + 5(1) + 3(-3) = 10
3(7) - (1) + 4(-3) = 8
5(7) - 2(1) + 7(-3) = 12
Then (7,1,-3) is a solution to system
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:)
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:
D
Step-by-step explanation:
In order to solve this we need to plug in the answer choices and make sure they work for BOTH answers!
Let us start with option A. (6,3) 3 = 4(6) + 6 = 3 = 30 This is automaticly wrong because 3 doesnt equal 30. There is no need to try it on the second equation since the first one was wrong.
Next answer choice, B (3,6) 6 = 2(3) = 6=6. The second equation works perfect for this. Now we have to make sure that it works for the first one as well. 6 = 4(3) + 6 = 6 = 18 which is wrong.
Next, C. (1,2) 2 = 2(1) = 2=2 Right now lets check the other equation.
2 = 4(1) + 6 = 2=10. Wrong
Last, D. (-3, -6) -6 = 2(-3) = -6 = -6 Right now lets check the other equation.
-6 = 4(-3) + 6 = -6 = -6. CORRECT. Answer choice D works for both equations.
Sorry for the wait of response.
Answer:
The drama club bought 35 t-shirt
Step-by-step explanation:
Let
t-shirt = x
Sweatshirt = y
Total cost = $795
They purchase 20 more tshirts than sweatshirts
x = y + 20
The equation is:
12x + 25y = 795
12(y + 20) + 25y = 795
12y + 240 + 25y = 795
37y = 795 - 240
37y = 555
y = 15
Substitute y = 15 into
x = y + 20
x = 15 + 20
x = 35
t-shirt = 35
Sweatshirt = 15
The drama club bought 35 t-shirt
