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3 years ago

Evaluate the expression: 6(a + b) where a = -3 and b = 6

Mathematics

1 answer:

levacccp [35]3 years ago

8 0

Answer here you go

Step-by-step explanation:

(-3 x 6 = -18)

6 x -18= -108

multiplication with postive and gegitives rule of thumb

negative times a positive equals a negative

negitive times a negative equals a positive

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What is 28-0.3=0.7-12

Anna71 [15]

It's a false statement.

On the left side, 28 - 0.3 = 27.7

On the right side, 0.7 - 12 = -11.3

The equation says that 27.7 is equal to -11.3 , but it's not.

8 0

3 years ago

Read 2 more answers

A tire manufacturer wants to estimate the average number of miles that may be driven in a tire of a certain type before the tire

alexandr402 [8]

Answer:

97% confidence interval for the average number of miles that may be driven is [26.78 miles, 33.72 miles].

Step-by-step explanation:

We are given that a random sample of tires is chosen and are driven until they wear out and the number of thousands of miles is recorded;

32, 33, 28, 37, 29, 30, 22, 35, 23, 28, 30, 36.

Firstly, the pivotal quantity for finding the confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample average number of miles = $\frac{\sum X}{n}$ = 30.25

s = sample standard deviation = $\sqrt{\frac{\sum (X-\bar X)^{2} }{n-1} }$ = 4.71

n = sample of tires = 12

$\mu$ = population average number of miles

Here for constructing a 97% confidence interval we have used One-sample t-test statistics as we don't know about population standard deviation.

So, 97% confidence interval for the population mean, $\mu$ is ;

P(-2.55 < $t_1_1$ < 2.55) = 0.97 {As the critical value of t at 11 degrees of

freedom are -2.55 & 2.55 with P = 1.5%}

P(-2.55 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 2.55) = 0.97

P( $-2.55 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $2.55 \times {\frac{s}{\sqrt{n} } }$ ) = 0.97

P( $\bar X-2.55 \times {\frac{s}{\sqrt{n} } }$ < $\mu$ < $\bar X+2.55 \times {\frac{s}{\sqrt{n} } }$ ) = 0.97

97% confidence interval for $\mu$ = [ $\bar X-2.55 \times {\frac{s}{\sqrt{n} } }$ , $\bar X+2.55 \times {\frac{s}{\sqrt{n} } }$ ]

= [ $30.25-2.55 \times {\frac{4.71}{\sqrt{12} } }$ , $30.25+2.55 \times {\frac{4.71}{\sqrt{12} } }$ ]

= [26.78 miles, 33.72 miles]

Therefore, 97% confidence interval for the average number of miles that may be driven is [26.78 miles, 33.72 miles].

7 0

4 years ago

Two angles are complementary. The degree measure of the larger angle is 2 more than 3 times the smaller angle. What is the degre

Aleksandr [31]

If they are complimentary that means both angles have a sum of 90 degrees.

A number that can only be added by the same number x2 is 30.

30 * 2 = 60

60 + 30 = 90

Therefore the larger angle is 60 degrees and the smaller angle is 30 degrees

8 0

3 years ago

PLEASE HURRY I DONT HAVE MUCH TIME

HACTEHA [7]

Answer:

Step-by-step explanation:

C. is correct bc it makes the most sense out of all of them just check my work by dividing by 2.

4 0

3 years ago

Solve for all values of x by factoring. x^2 - 3x – 1 = -3x

dusya [7]

Answer:

x = 1, x = -1

Step-by-step explanation:

x^2 - 3x - 1 = -3x

Simplify...

x^2 - 3x - 1 + 3x = 0

x^2 - 1 = 0

Use this formula to factor: (a-b)(a+b) = a^2 - b^2

So x^2 - 1 will factor to...

(x-1)(x+1)

Solve for the equation: (x-1)(x+1) = 0

x - 1 =0

x = 1

x + 1 = 0

x = -1

6 0

3 years ago