It'd be easier to do #18 if y ou were to break it up:
14* (first term + 14th term)
Sum from n=1 to 14 of n = S = ---------------------------------
14 2
14(1+14)
= ---------------- = 7(15) = 105
2
The sum of twice that is 210. The sum of "1 from n=1 to n=14" is just 14.
The final sum is 210 + 14 = 224 (answer)
A Pythagorean triple is a set of thre integer numbers, a, b and c that meet the Pythgorean theorem a^2 + b^2 = c^2
Use Euclide's formula for generating Pythagorean triples.
This formula states that given two arbitrary different integers, x and y, both greater than zero, then the following numbers a, b, c form a Pythagorean triple:
a = x^2 - y^2
b = 2xy
c = x^2 + y^2.
From a = x^2 - y^2, you need that x > y, then you can discard options A and D.
Now you have to probe the other options.
Start with option B, x = 4, y = 3
a = x^2 - y^2 = 4^2 - 3^2 = 16 -9 = 7
b = 2xy = 2(4)(3) = 24
c = x^2 9 y^2 = 4^2 + 3^2 = 16 + 9 = 25
Then we could generate the Pythagorean triple (7, 24, 25) with x = 4 and y =3.
If you want, you can check that a^2 + b^2 = c^2; i.e. 7^2 + 24^2 = 25^2
The answer is the option B. x = 4, y = 3
Answers
1) 4
2) 0, 2, -10
3) 0, 5, -2
Step-by-step explanation:
1) x³ - 64 = 0
x³ = 64
x = 4
2) x³(x² + 8x - 20) = 0
x³(x² + 10x - 2x - 20) = 0
x³(x(x + 10) - 2(x + 10)) = 0
x³(x + 10)(x - 2) = 0
x = 0, 2, -10
3) x³ - 3x² - 10x = 0
x(x² - 3x - 10) = 0
x(x² - 5x + 2x - 10) = 0
x(x(x - 5) + 2(x - 5)) = 0
x(x - 5)(x + 2) = 0
x = 0, 5, -2
Answer:
37.5%
Step-by-step explanation:
Ratio = 3 : 5
Total part = 3 +5 = 8
Chocolate donuts = 3/8
= 37.5 %
