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2 years ago

Simplify 7 x + 2 x + 5 y - 2 y 9 x + 3 y 12 xy 9 x + 7 y

Mathematics

1 answer:

solniwko [45]2 years ago

6 0

U didn’t include the addition sign or sub sign for some of them

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What is the area of a triangle with base b = 3 cm and height h = 4 cm?

maxonik [38]

Step-by-step explanation:

The area of triangle is

=21×height×base=21×3×4=3×2=6 cm2

6 0

1 year ago

Find the general solution of x'1 = 3x1 - x2 + et, x'2 = x1.

Ann [662]

Note that if ${x_2}'=x_1$ , then ${x_2}''={x_1}'$ , and so we can collapse the system of ODEs into a linear ODE:

${x_2}''=3{x_2}'-x_2+e^t$
${x_2}''-3{x_2}'+x_2=e^t$

which is a pretty standard linear ODE with constant coefficients. We have characteristic equation

$r^2-3r+1=\left(r-\dfrac{3+\sqrt5}2\right)\left(r+\dfrac{3+\sqrt5}2\right)=0$

so that the characteristic solution is

${x_2}_C=C_1e^{(3+\sqrt5)/2\,t}+C_2e^{-(3+\sqrt5)/2\,t}$

Now let's suppose the particular solution is ${x_2}_p=ae^t$ . Then

${x_2}_p={{x_2}_p}'={{x_2}_p}''=ae^t$

and so

$ae^t-3ae^t+ae^t=-ae^t=e^t\implies a=-1$

Thus the general solution for $x_2$ is

$x_2=C_1e^{(3+\sqrt5)/2\,t}+C_2e^{-(3+\sqrt5)/2\,t}-e^t$

and you can find the solution $x_1$ by simply differentiating $x_2$ .

7 0

3 years ago

Mrs. Dugan plans to serve 100 barbecue sandwiches at the company picnic. How many packages of barbecue buns will she need if bun

Aleonysh [2.5K]

100 sandwiches, using bun packages of 8...

100/8=12.5 Since you cant buy a half a package, round up to 13 packages

100 sandwiches, using bun packages of 12...

100/12=8.33 Since you cant have a third of a package, round up to 9 packages

6 0

2 years ago

5. James makes $15.50 per hour and works 40 hours a week. He pays 26% of his gross earnings in federal and state

QveST [7]

9514 1404 393

Answer:

Step-by-step explanation:

On average, there are about 173 1/3 hours per month, so James's take-home pay will be about ...

($15.50/h)(173 1/3 h/mo)(1 -26%) = $1988.13

His proposed rental is about ...

1400/1988.13 · 100% = 70.4%

of his take-home pay.

Most financial planners would recommend the percentage be well below 50%. It is unlikely James can make his proposed monthly payments.

4 0

3 years ago

Suppose that a is a one-dimensional array of ints with a length of at least 2. Which of the following code fragments successfull

elixir [45]

Answer:

E)II and III only

Step-by-step explanation:

This can be seen with examples. Say a[0]=1 and and a[1]=2.

for I , the first line of code would be:

a[0]=a[1];

thus, we would get a new value for a[0]=2.

The second line of code

a[1]=a[0]; uses the new value of a[0], so we would get a[1]=2.

The end result is a[0]=2, and a[1]=2 which doesn't exchange the values of the first two elements.

For II the first line of code

int t= a[0]; saves the original value of a[0] to t, so we get t=1.

the second line of code

a[0]=a[1]; changes the value of a[0] to that of a[1]. Thus, in our example a[0]=2.

the final line

a[1]=t; changes the value of a[1] to the original value of a[0], giving us a[1]=1 and a[0]=2, what we were looking for.

For III

the first line of code

a[0]=a[0]-a[1];

gives us

a[0]=1-2

the secon line

a[1]=a[1]+a[0];

takes the new value of a[0] and replaces it in the expression

a[1]= 2+(1-2)=1

the last line

a[0]=a[1]-a[0];

takes the new value of a[0] and a[1] and replaces the in the expression

a[0]=1-(1-2)=1-1+2=2

which exchanges the values needed.

So we can see that only II and III do what we require, giving us E as the answer.

6 0

2 years ago