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viktelen [127]
2 years ago
9

An equation and the first step in its solution are shown: Equation: x2 + 8x - 9 = 0

Mathematics
1 answer:
Novay_Z [31]2 years ago
3 0
Answer- A-16

Because when doing completing the square, you divide the coefficient of x by 2, which is 4, and the square it which is 16
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Let C(n, k) = the number of k-membered subsets of an n-membered set. Find (a) C(6, k) for k = 0,1,2,...,6 (b) C(7, k) for k = 0,
vladimir1956 [14]

Answer:

(a) C(6,0) = 1, C(6,1) = 6, C(6,2) = 15, C(6,3) = 20, C(6,4) = 15, C(6,5) = 6, C(6,6) = 1.

(b) C(7,0) = 1, C(7,1) = 7, C(7,2) = 21, C(7,3) = 35, C(7,4) = 35, C(7,5) = 21, C(7,6) = 7, C(7,7)=1.

Step-by-step explanation:

In this exercise we only need to recall the formula for C(n,k):

C(n,k) = \frac{n!}{k!(n-k)!}

where the symbol n! is the factorial and means

n! = 1\cdot 2\cdot 3\cdot 4\cdtos (n-1)\cdot n.

By convention 0!=1. The most important property of the factorial is n!=(n-1)!\cdot n, for example 3!=1*2*3=6.

(a) The explanations to the solutions is just the calculations.

  • C(6,0) = \frac{6!}{0!(6-0)!} = \frac{6!}{6!} = 1
  • C(6,1) = \frac{6!}{1!(6-1)!} = \frac{6!}{5!} = \frac{5!\cdot 6}{5!} = 6
  • C(6,2) = \frac{6!}{2!(6-2)!} = \frac{6!}{2\cdot 4!} = \frac{5!\cdot 6}{2\cdot 4!} = \frac{4!\cdot 5\cdot 6}{2\cdot 4!} = \frac{5\cdot 6}{2} = 15
  • C(6,3) = \frac{6!}{3!(6-3)!} = \frac{6!}{3!\cdot 3!} = \frac{5!\cdot 6}{6\cdot 6} = \frac{5!}{6} = \frac{120}{6} = 20
  • C(6,4) = \frac{6!}{4!(6-4)!} = \frac{6!}{4!\cdot 2!} = frac{5!\cdot 6}{2\cdot 4!} = \frac{4!\cdot 5\cdot 6}{2\cdot 4!} = \frac{5\cdot 6}{2} = 15
  • C(6,5) = \frac{6!}{5!(6-5)!} = \frac{6!}{5!} = \frac{5!\cdot 6}{5!} = 6
  • C(6,6) = \frac{6!}{6!(6-6)!} = \frac{6!}{6!} = 1.

(b) The explanations to the solutions is just the calculations.

  • C(7,0) = \frac{7!}{0!(7-0)!} = \frac{7!}{7!} = 1
  • C(7,1) = \frac{7!}{1!(7-1)!} = \frac{7!}{6!} = \frac{6!\cdot 7}{6!} = 7
  • C(7,2) = \frac{7!}{2!(7-2)!} = \frac{7!}{2\cdot 5!} = \frac{6!\cdot 7}{2\cdot 5!} = \frac{5!\cdot 6\cdot 7}{2\cdot 5!} = \frac{6\cdot 7}{2} = 21
  • C(7,3) = \frac{7!}{3!(7-3)!} = \frac{7!}{3!\cdot 4!} = \frac{6!\cdot 7}{6\cdot 4!} = \frac{5!\cdot 6\cdot 7}{6\cdot 4!} = \frac{120\cdot 7}{24} = 35
  • C(7,4) = \frac{7!}{4!(7-4)!} = \frac{6!\cdot 7}{4!\cdot 3!} = frac{5!\cdot 6\cdot 7}{4!\cdot 6} = \frac{120\cdot 7}{24} = 35
  • C(7,5) = \frac{7!}{5!(7-2)!} = \frac{7!}{5!\cdot 2!} = 21
  • C(7,6) = \frac{7!}{6!(7-6)!} = \frac{7!}{6!} = \frac{6!\cdot 7}{6!} = 7
  • C(7,7) = \frac{7!}{7!(7-7)!} = \frac{7!}{7!} = 1

For all the calculations just recall that 4! =24 and 5!=120.

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It takes half of a yard of ribbon to make a bow. How many bows
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I believe the shirts are different (in color, in size, in style,...), is so then:

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Stels [109]

the probability of an event occurring, it is easy to compute the probability that the event does not occur. If P(A) is the probability of Event A, then 1 - P(A) is the probability that the event does not occur. For the last example, the probability that the total is 6 is 5/36.

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2 years ago
Write the given roots to quadratic equation
Svet_ta [14]

Answer:

α + β = - ba and αβ = ca.

⇒ x2 + bax + ca = 0 (Since, a ≠ 0)

⇒ x2 - (α + β)x + αβ = 0, [Since, α + β = -ba and αβ = ca]

Step-by-step explanation:

pls mark brainlist

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