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4 years ago

12

I need to make this expression true by using grouping symbols. 2x2+3^2 -4+3x5

1 answer:

Novay_Z [31]4 years ago

7 0

Simply 3^2 to 9

2×2+9−4+3×5

Simplify 2 x 2 to 4

4+9−4+3×5

Simplify 3 x 5 to 15

4+9−4+15

Simplify

= 24

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Edward has 30 sweets.

lianna [129]

Answer:

20 red sweets

Step-by-step explanation:

do two thirds of 30 and the part that cane out is the red sweets

3 0

3 years ago

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A sample of 125 pieces of yarn had mean breaking strength 6.1 N and standard deviation 0.7 N. A new batch of yarn was made, usin

AlexFokin [52]

Answer:

The 90% confidence interval for the difference in mean breaking strength between the two types of yarn is (0.08N, 0.52N).

Step-by-step explanation:

Before building the confidence interval, we need to understand the central limit theorem and subtraction of normal variables.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Subtraction of normal variables:

When we subtract two normal variables, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

A sample of 125 pieces of yarn had mean breaking strength 6.1 N and standard deviation 0.7 N.

This means that $\mu_1 = 6.1, s_1 = \frac{0.7}{\sqrt{125}} = 0.0626$

In a sample of 75 pieces of yarn from the new batch, the mean breaking strength was 5.8 N and the standard deviation was 1.0 N.

This means that $\mu_2 = 5.8, s_2 = \frac{1}{\sqrt{75}} = 0.1155$

Distribution of the difference:

$\mu = \mu_1 - \mu_2 = 6.1 - 5.8 = 0.3$

$s = \sqrt{s_1^2+s_2^2} = \sqrt{0.0626^2+0.1155^2} = 0.1314$

Confidence interval:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.9}{2} = 0.05$

Now, we have to find z in the Ztable as such z has a pvalue of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.05 = 0.95$ , so Z = 1.645.

Now, find the margin of error M as such

$M = zs$

$M = 1.645*0.1314 = 0.22$

The lower end of the interval is the sample mean subtracted by M. So it is 0.3 - 0.22 = 0.08N

The upper end of the interval is the sample mean added to M. So it is 0.3 + 0.22 = 0.52N

The 90% confidence interval for the difference in mean breaking strength between the two types of yarn is (0.08N, 0.52N).

3 0

3 years ago

PLS ANSWER I MARK AS BRAINESLT The following shows the use of the converse of the Pythagorean Theorem using side lengths of four

KatRina [158]

It would be the first one because if you do 4^2+4^2 it does NOT equal 32 it equals a even greater number. So the first one is not a right triangle

3 0

3 years ago

Evaluate log2 1 over 64.

Nastasia [14]

Let log2 (1/64) = x. Then,

2^x = 1/64

2^x = 1/(2^6)

2^x = 2^(-6)

So,

x = -6

log2 (1/64) = -6 <----- this is the answer.

I hope this helps. =)

6 0

3 years ago

Solve the equation for x. 2x + 22 = 4(x+3)

shusha [124]

Answer:

x = 5

Step-by-step explanation:

We have the algebraic expression and are asked to solve for x.

To solve, we need to isolate x.

2x + 22 = 4(x + 3)

Distribute :

2x + 22 = (4(x) + 4(3))

2x + 22 = 4x + 12

Subtract 12 from both sides :

2x + 10 = 4x

4x = 2x + 10

Subtract 2x from both sides :

2x = 10

Divide 2 from both sides to get x alone :

x = 5

5 0

3 years ago

Read 2 more answers