Answer:
what equation silly
Step-by-step explanation:
You have to do substitution in both sides e) (-4,2)
Answer:
x=2
Step-by-step explanation:
Step-by-step explanation:
(a²-b²)(c²-d²) = a²c² - a²d² - b²c² + b²d²
(b²-d²)(c²-a²) = b²c² - a²b² - c²d² + a²d²
the sum of both is
a²c² + b²d² - a²b² - c²d² = a²(c²-b²) + d²(b²-c²) =
= a²(c²-b²) - d²(c²-b²) = (c²-b²)(a²-d²) = 2021
after a little check we find 2021 is only divisible by 43 and 47 (or 1 and 2021).
so, it is clear that our expression resembles
43×47 = 2021
that means that e.g. c²-b² = 43, and a²-d² = 47
or the other way around, it does not matter.
what squared integer numbers give a difference of 43 ? and 47 ?
squared numbers
1 4 9 16 25 36 49 64 81 100 121 144 169 196 225 256
289 324 361 400 441 484 529 576
aha ! 484 - 441 = 43
and 576 - 529 = 47
so, we get
a = sqrt(576) = 24
b = sqrt(441) = 21
c = sqrt(484) = 22
d = sqrt(529) = 23
one could also use the formula for consecutive squared numbers
(n+1)² = n² + 2n + 1
under the assumption that the 2 numbers are convective (which it turns out they are in this example) we get
(n+1)² - n² = 2n + 1 = 43
2n = 42
n = 21
n+1 = 22
and for 47
2n + 1 = 47
2n = 46
n = 23
n+1 = 24
The probability of winning exactly 21 times is:-0.32
Given,
The probability of winning on an arcade game, p = 0.659
Number of times you play arcade game, n = 30
By assuming this as a normal distribution, we get
Mean=μ=30×0.659 =19.77
Standard deviation, σ = 
= 
≈ 2.60
Let X be a binomial variable
Then, the z score for x = 21 will be:
z = (x - μ) / σ = 
≈ 0.47
Now, the probability of winning exactly 21 times
P (x ≥ z) = P (21 ≥ 0.47) = 0.32
Hence the probability of winning exactly 21 times is 0.32
Learn more about probability here:-brainly.com/question/13067945
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