Each number in the sum is even, so we can remove a factor of 2.
2 + 4 + 6 + 8 + ... + 78 + 80 = 2 (1 + 2 + 3 + 4 + ... + 39 + 40)
Use whatever technique you used in (a) and (b) to compute the sum
1 + 2 + 3 + 4 + ... + 39 + 40
With Gauss's method, for instance, we have
S = 1 + 2 + 3 + ... + 38 + 39 + 40
S = 40 + 39 + 38 + ... + 3 + 2 + 1
2S = (1 + 40) + (2 + 39) + ... + (39 + 2) + (40 + 1) = 40×41
S = 20×21 = 420
Then the sum you want is 2×420 = 840.
Answer:
y-intercept: (0, 5)
Step-by-step explanation:
This parabola has an equation of -x² + 4x + 5.
It's y-intercept is (0, 5).
It's x-intercepts or roots are (-1, 0) and (5, 0).
It's vertex is (2, 9).
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Keep in mind that the y-intercept is when x = 0.
Answer:
so
Step-by-step explanation:
i would try C bc it has both 73 degrees and 83 degrees and i dont really know what SAS is besides it means side angle side??? if its right can i have brainlest
Answer:
Add all the digits.
If the sum of digits is a multiple of 3, the number is too
