Solving these quadratics for x using complete the square 3x^2-4x-1=0. Show your work.

1 answer:

6 0

Answer: x = (sqrt(7) + 2)/3 and
x = ( – sqrt(7) + 2)/3

Explanation:

3x^2 - 4x - 1 = 0

Divide both sides by 3:

3x^2/3 - 4/3x - 1/3 = 0/3
x^2 - 4/3x - 1/3 = 0
x^2 - 4/3x = 1/3
x^2 - 4/3x + (2/3)^2 = 1/3 + (2/3)^2
(x - 2/3)^2 = 1/3 + 4/9
(x - 2/3)^2 = 7/9

Sqrt both sides:

x - 2/3 = sqrt (7/9)
x - 2/3 = |sqrt(7)/3|

Set x -2/3 = sqrt(7)/3

=> x = (sqrt(7) + 2)/3

Set x - 2/3 = - sqrt(7)/3

=> x = ( - sqrt(7) + 2)/3

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Margie is practicing for an upcoming tennis tournament. Her first serve is good 20 out of 30 times on average. Margie wants to k

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Answer:

0.6804

Step-by-step explanation:

Given that Margie is practicing for an upcoming tennis tournament. Her first serve is good 20 out of 30 times on average.

Since each trial is independent and there are two outcomes, X no of good serves is binomial with n=6 and p =2/3

Required probability

= Prob that atleast four of 6 times good serve

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