All categories

3 years ago

!!! HELP ME !!!

Mathematics

1 answer:

antoniya [11.8K]3 years ago

4 0

Answer:

DHGB

Step-by-step explanation:

Let's start with 1.

The equation is in standard form (ax+by=c): -4x+2y=8

we'll put it into slope intercept form.

Add 4x onto both sides

2y=4x+8

divide by 2

y=2x+4

Parallel lines have the same slope, but a different y intercept. (the line parallel to this one will have a slope of 2 but a y intercept different from +4)

Looking at the answer choices, the only choice with a slope of 2 is D (y=2x-5)

So the answer to 1 is D

Now 2.

we're given 3 points. One of the points crosses the y axis, which is the y intercept. In this case, the line crosses the point (0,3)

That means the y intercept of the line is (0,3)

here's the line so far:

y=mx+3 (m is a placeholder for the slope)

when given a graph, we can use rise/run. Starting from the point (3,2), we can move 3 spaces to the left, and one up.

In a graph, if you move to the left or downwards, it's a negative move. If you move up or to the right, it's a positive move.

Since we went 1 space up (rise) and 3 spaces to the left, (run) the slope is -1/3

So the line is y=-1/3x+3

Perpendicular lines are negative and reciprocal. If you multiply their slopes, they will equal -1. Their y intercepts don't matter at all.

So to find the slope, we can use this equation.

-1/3m=-1

multiply by -3 on both sides

m=3

Looking at the answer choices, H is the only answer with a slope of 3. So the answer to 2 is H.

Now, 3

You can do the graph method like above for 2, but I'll just calculate the slope.

We're given two points, (-1,-2) and (0,2)

the formula for slope is (y2-y1)/(x2-x1)

we can label the points.

x1=-1

y1=-2

x2=0

y2=2

now, substitute into the equation.

m=(2--2)/(0--1)

m=4/1

the slope is 4.

Now let's use point slope form, which is y-y1=m(x-x1)

once again, sub. into the equation.

y+2=4(x+1)

do distributive prop

y+2=4x+4

subtract by 2

y=4x+2

As said above, parallel lines have the same slope.

Looking at the answer options, G also has the slope of 4

so the answer to 3 is G

Finally, #4

Equation: 3x+y=1

subtract 3x from both sides

y=-3x+1

As said above, perpendicular lines have slopes that multiply to equal -1.

-3m=-1

multiply by -1/3

m=1/3

so the slope of the line will be 1/3.

Looking at the answer options, B also has a slope of 1/3.

So the answer to 4 is B

The code is DHGB

Hope this helps!

You might be interested in

If the pattern shown continues how many black keys appear on an organ with a total of 240 keys

andre [41]

240 is probably multiplied some other number if theres another number on there to multiply or divide by.

6 0

3 years ago

Express 0.88 as a percent

Alekssandra [29.7K]

Answer:

88%

Step-by-step explanation:

0.88*100=88%

5 0

3 years ago

Read 2 more answers

A random sample of 9 wheels of cheese yielded the following weights in pounds has a sample mean of 20.90 and a sample variance o

Ronch [10]

Answer:

$2.002 \leq \sigma^2 \leq 11.365$

Step-by-step explanation:

1) Data given and notation

s represent the sample standard deviation

$s^2$ represent the sample variance

n=9 the sample size

Confidence=90% or 0.90

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi Square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case we need to find the sample standard deviation with the following formula:

$s=sqrt{\frac{\sum_{i=1}^9 (x_i -\bar x)^2}{n-1}}
The sample variance given was [tex]s^2=3.45$

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=9-1=8$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical values.