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2 years ago

(-7)-(1.2x)+19+7.7x simplified

Mathematics

1 answer:

kenny6666 [7]2 years ago

8 0

Answer:

6.5x+12

Step-by-step:

-7-1.2x+19+7.7x

=6.5x+12

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If x² + xy – 3y = 3, then at the point (2, 1), dy/dx

Scilla [17]

Answer:

Step-by-step explanation:

We have the equation:

$x^2+xy-3y=3$

Take the derivative of both sides with respect to x:

$\frac{d}{dx}[x^2+xy-3y]=\frac{d}{dx}[3]$

Implicitly differentiate:

$2x+y+x\frac{dy}{dx}-3\frac{dy}{dx}=0$

Solve for dy/dx:

$\frac{dy}{dx}(x-3)=-2x-y\\$

Divide:

$\frac{dy}{dx}=-\frac{2x+y}{x-3}$

To find dy/dx at (2, 1), substitute 2 for x and 1 for y. So:

$\frac{dy}{dx}_{(2, 1)}=-\frac{2(2)+1}{2-3}=-\frac{5}{-1}=5$

Hence, our answer is A.

4 0

3 years ago

It takes 3 hours to paddle a kayak 12 miles downstream and 4 hours for the return trip upstream. Find the rate of the kayak in s

Furkat [3]

The rate of the kayak in still water is 3.5 mph

<h3>Solution:</h3>

Given that It takes 3 hours to paddle a kayak 12 miles downstream

Distance covered in downstream = 12 miles

Time taken to cover downstream = 3 hours

Also given that it takes 4 hours for the return trip upstream

Distance covered in upstream = 12 miles

Time taken to cover upstream = 4 hours

Formula to remember:

If the speed of a boat in still water is u km/hr and the speed of the stream is v km/hr, then: Speed downstream = (u + v) km/hr and Speed upstream = (u - v) km/hr

Let the speed of Kayak in still water = x mph

And The speed of current = y mph

For downstream:

Speed downstream = x + y

We know that $speed = \frac{distance}{time}$

$\frac{distance}{time} = x + y$

$x + y = \frac{12}{3}$

x + y = 4 ------ eqn 1

For upstream:

Speed upstream = x - y

$\frac{12}{4} = x - y$

x - y = 3 -------- eqn 2

Now let us eqn 1 and eqn 2

Add eqn 1 and eqn 2

x + y + x - y = 4 + 3

2x = 7

x = 3.5

speed of Kayak in still water = x mph = 3.5 mph

6 0

3 years ago

EXTRA POINTS x/4 ÷ 2/3 = 1/5 solve for x

nikitadnepr [17]

Answer:

x=40

Step-by-step explanation:

first you simplify both sides of the equation, then you isolate the variable

40/4= 10

10 times 3/2 = 15

8 0

2 years ago

Solve for x 54 = 9(x+3)

sladkih [1.3K]

The answer to this question is

7 0

3 years ago

Read 2 more answers

The following correlations were computed as part of a multiple regression analysis that used education, job, and age to predict

erma4kov [3.2K]

Answer:

Job has the weakest association with the dependent variable income.

Step-by-step explanation:

The correlation coefficient is used to determine the the strength and direction of the relationship between two variables.

It is denoted by r and the value of r ranges from -1.00 to 1.00.

The correlation data provided is as follows:

Income Education Job Age

Income 1.000

Education 0.677 1.000

Job 0.173 -0.181 1.000

Age 0.369 0.073 0.689 1.000

The dependent variable is the income.

And the variables Education, Job and Age are independent variables.

The correlation between Income and Job is 0.173.

This is the lowest correlation coefficient between the dependent and independent variable.

Thus, Job has the weakest association with the dependent variable income.

8 0

3 years ago