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denis23 [38]
3 years ago
12

Answer these three please!!

Mathematics
1 answer:
katen-ka-za [31]3 years ago
6 0

Answer:

10. x = 3 ± 2√6

11. x = 4 ± √6

12. x = \frac{- 7 + \sqrt{109}}{10} and x = \frac{- 7 - \sqrt{109}}{10}

Step-by-step explanation:

10. Given the quadratic equation (x - 3)² + 14 = 38

We have to solve it by square root.

Now, (x - 3)² + 14 = 38

⇒ (x - 3)² = 38 - 14 = 24

⇒ (x - 3)² = (2√6)²

Now, square rooting both sides we get,

(x - 3) = ± 2√6

⇒ x = 3 ± 2√6 (Answer)

11. Given the quadratic equation x² - 8x + 10 = 0

We have to solve it by completing the square.

Now, x² - 8x + 10 = 0

⇒ x² - 2(4)(x) + 4² = 4² - 10

⇒ (x - 4)² = (√6)²

Now, square rooting both sides we get,

x - 4 = ± √6

⇒ x = 4 ± √6 (Answer)

12. Given the quadratic equation 5x² + 7x - 3 = 0

We have to solve it by quadratic formula.

Hence,

x = \frac{- 7 + \sqrt{7^{2} - 4 (5)(- 3)}}{2(5)} and x = \frac{- 7 - \sqrt{7^{2} - 4 (5)(- 3)}}{2(5)}

⇒ x = \frac{- 7 + \sqrt{109}}{10} and x = \frac{- 7 - \sqrt{109}}{10} (Answer)

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Let f(x) = 1/x . Find the number b such that the average rate of change of f on the interval [2, b] is − 1/8
vekshin1

Answer:

b=4

Step-by-step explanation:

So, we have the function f(x)=1/x. We need to find b such that the average rate of change or the slope is -1/8 between the intervel [2, b]. First, let's find f(2).

f(2) = 1/(2) = 1/2

So, we have the point (2, 1/2)

At point b, f(b) = 1/b.

Let's plug this into the slope formula:

\frac{y_2-y_1}{x_2-x_1}=\frac{.5-\frac{1}{b} }{2-b}  =-1/8

Now, we just need to solve for b. First, let's multiply both the numerator and denominator by b (to get rid of the annoying fraction in the numerator).

\frac{.5b-1}{2b-b^2} =\frac{-1}{8}

Now, cross multiply.

4b-8=b^2-2b

b^2-6b+8=0

Solve for b. Factor using the numbers -4 and -2.

=(b-4)(b-2)=0

Thus, b=4 or b=2.

However, b=2 is not a possible solution since the interval [2,2] means nothing. Thus, b=4.

4 0
3 years ago
In a school of 330 students, 85 of them are in a drama club, 200 of them are in a sports team and 60 of them do both
Neko [114]

Answer:

105/330 = 21/66 = 7/22

7/22 is the answer I think

Step-by-step explanation:

n(U) = 330

n(A) = 85

n(B) = 200

n(A n B) = 60

Now,

n(A U B) = n(A) + n(B) - n(A n B)

or, n(A U B) = 85 + 200 - 60

or, n(A U B) = 285 - 60 = 225

Now,

n(A U B) compliment = n(U) - n(A U B)

n(A U B) compliment = 330 - 225

so, n(A U B) compliment = 105

Now,

probability = 105/330

8 0
2 years ago
Whats the answer for 4 and 5? Please I need the answers ASAP.
olga nikolaevna [1]

Answer:

4. 6/15

Step-by-step explanation:

5. 5/3 is the an answer

8 0
2 years ago
Y=-5over4x+7 what is the slope pf a line parallel to this line? What is the slope of a line perpendicular?
quester [9]
You question isn't clear, but I assume that you are asking for the slop of a line parallel to y=-(5/4)(x)+7.
The line parallel would have a slop of -5/7 and the line perpendicular would have a slop of 5/7. 
The difference between the two answers is the sign of the two slopes, one is positive the other is negative

4 0
3 years ago
A national study, that revealed a normal distribution, revealed that the average time a student spends studying statistics on a
Neporo4naja [7]

Answer:

Null hypothesis = H0 : μ = 60

Alternative hypothesis = H1 : μ < 60

Step-by-step explanation:

From the question given :

μ = 60 minutes

xbar = 44.27 minutes

s = 20.4 minutes

The alternative hypothesis is the claim ; which is to hypothesize that the average studying time is 44.27 (which is less than the population average studying time)

The null hypothesis is the initial truth and it is the opposite of the alternative hypothesis.

The hypothesis are :

H0 : μ = 60

H1 : μ < 60

5 0
2 years ago
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