9514 1404 393
Answer:
(c) 2440
Step-by-step explanation:
The sum of the squares of numbers 1 .. n is ...
s(n) = n(n +1)(2n +1)/6
You want the sum of squares from 5 to 19. We can compute that from ...
s(19) -s(4) = (19(20)(39) -4(5)(9))/6 = (14820 -180)/6 = 2440
The page he will read next is 145
Answer:
The answer to your question is:
61.- 25
62.- 26
Step-by-step explanation:
61.-
2(5x + 5) + 2(2x) = 360
10x + 10 + 4x = 360
14x = 360 - 10
14x = 350
x = 350/14
x = 25
62.-
2(4x - 4) + 2(3x + 2) = 360
8x - 8 + 6x + 4 = 360
14x - 4 = 360
14x = 360 + 4
14x = 364
x = 364 / 14
x = 26
I attached a picture, see if you can see what I'm doing. Basically, I start by squaring everything to get rid of the radical, but just remember at the end to always, always check your answers, because squaring your answers could get rid of some negative numbers that could result in imaginary answers. The answer I came up with was a=5,-2
