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.
I doesn’t let me see the photo I’m very good at this but I just don’t understand your question
20 cups of oats, and here’s your table!
5 + 5 is 10...
Start with 5 on one hand and use the other hand (count 5 on that one)
Word problem to make this a little bit 'simplier'
You have 5 squares (◾◾◾◾◾) and you tag along have more (◾◾◾◾◾). How many do you have all together? 10 squares.
◾◾◾◾◾ + ◾◾◾◾◾ (⬅count those squares )
Answer:
Step-by-step explanation:
line given is x-y+1= 0
you can rewrite it in slope intercept y=mx+b where m is the slope, and b is the y-intercept where the line meets the y-axis
x-y+1 =0 subtract x and 1 from both sides of the equation
-y = -x-1 multiply both sides by -1
y = x+1 so the slope of this line is 1 and the y-intercept is 1
If you draw this line you can see that there are actually 2 lines that form 45° angles with y=x+1 and pass through (-1, 2), one is vertical x= -1 and one horizontal y =2
