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3 years ago

Which of these shows the result of using the first equation to substitute for y in the second equation then combing like terms

Mathematics

1 answer:

AnnyKZ [126]3 years ago

8 0

$2x + 3y = 55$

$2x + 3(3x) = 55$

$2x + 9x = 55$

$11x = 55$

$\frac{11x}{11} = \frac{55}{11}$

x=5

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HELP ASAP , algebra 1 giving BRAINLIEST , no guessing,

katovenus [111]

Answer:

The answer is B that is the answer

5 0

3 years ago

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Write a paragraph to help Miguel explain to Hannah how to complete the problems. Be sure to explain the process step-by-step (re

Eddi Din [679]

Steps in multiplying fractions. Remember: finding common denominator is not necessary in multiplying fractions.
Common denominators are only needed in adding and subtracting fractions.

14/15 * 5/2

Step 1. Multiply the numerators.
14 * 5 = 70
Step 2. Multiply the denominators
15 * 2 = 30
Step 3. Simplify the fraction.
70/30 = 2 10/30 = 2 1/3

*the fraction 10/30 can still be simplified by dividing both numbers by 10. Hence, 1/3.

Steps in Dividing fractions.

24/60 ÷ 8/15

Step 1. Get the reciprocal of the 2nd fraction. Reciprocal means the reverse of the fraction. Simply swap the places of the numbers.

Reciprocal of 8/15 is 15/8.

Step 2. Multiply the 1st fraction to the reciprocal of the 2nd fraction. Follow steps in multiplying fractions.

24/60 * 15/8 = (24*15) / (60*8) = 360/480

Step 3. Simplify the fraction.
360/480 = 9 / 12 = 3/4

360 ÷ 40 = 9 ; 9 ÷ 3 = 3
480 ÷ 40 = 12 ; 12 ÷ 3 = 4

4 0

2 years ago

Apply the method of undetermined coefficients to find a particular solution to the following system.wing system.

jarptica [38.1K]

$y''-y'+y=\sin x$

The corresponding homogeneous ODE has characteristic equation $r^2-r+1=0$ with roots at $r=\dfrac{1\pm\sqrt3}2$ , thus admitting the characteristic solution

$y_c=C_1e^x\cos\dfrac{\sqrt3}2x+C_2e^x\sin\dfrac{\sqrt3}2x$

For the particular solution, assume one of the form

$y_p=a\sin x+b\cos x$

${y_p}'=a\cos x-b\sin x$

${y_p}''=-a\sin x-b\cos x$

Substituting into the ODE gives

$(-a\sin x-b\cos x)-(a\cos x-b\sin x)+(a\sin x+b\cos x)=\sin x$

$-b\cos x+a\sin x=\sin x$

$\implies a=1,b=0$

Then the general solution to this ODE is

$\boxed{y(x)=C_1e^x\cos\dfrac{\sqrt3}2x+C_2e^x\sin\dfrac{\sqrt3}2x+\sin x}$

$y''-3y'+2y=e^x\sin x$

$\implies r^2-3r+2=(r-1)(r-2)=0\implies r=1,r=2$

$\implies y_c=C_1e^x+C_2e^{2x}$

Assume a solution of the form

$y_p=e^x(a\sin x+b\cos x)$

${y_p}'=e^x((a+b)\cos x+(a-b)\sin x)$

${y_p}''=2e^x(a\cos x-b\sin x)$

Substituting into the ODE gives

$2e^x(a\cos x-b\sin x)-3e^x((a+b)\cos x+(a-b)\sin x)+2e^x(a\sin x+b\cos x)=e^x\sin x$

$-e^x((a+b)\cos x+(a-b)\sin x)=e^x\sin x$

$\implies\begin{cases}-a-b=0\\-a+b=1\end{cases}\implies a=-\dfrac12,b=\dfrac12$

so the solution is

$\boxed{y(x)=C_1e^x+C_2e^{2x}-\dfrac{e^x}2(\sin x-\cos x)}$

$y''+y=x\cos(2x)$

$r^2+1=0\implies r=\pm i$

$\implies y_c=C_1\cos x+C_2\sin x$

Assume a solution of the form

$y_p=(ax+b)\cos(2x)+(cx+d)\sin(2x)$

${y_p}''=-4(ax+b-c)\cos(2x)-4(cx+a+d)\sin(2x)$

Substituting into the ODE gives

$(-4(ax+b-c)\cos(2x)-4(cx+a+d)\sin(2x))+((ax+b)\cos(2x)+(cx+d)\sin(2x))=x\cos(2x)$

$-(3ax+3b-4c)\cos(2x)-(3cx+3d+4a)\sin(2x)=x\cos(2x)$

$\implies\begin{cases}-3a=1\\-3b+4c=0\\-3c=0\\-4a-3d=0\end{cases}\implies a=-\dfrac13,b=c=0,d=\dfrac49$

so the solution is

$\boxed{y(x)=C_1\cos x+C_2\sin x-\dfrac13x\cos(2x)+\dfrac49\sin(2x)}$

7 0

2 years ago

What is 3d+8=2d-7 is equations

fredd [130]

3d + 8 = 2d - 7 equals d = -15.

First, subtract 2d from both sides. Your problem should look like: 3d + 8 - 2d = -7.
Second, simplify 3d + 8 - 2d to get d + 8. Your problem should look like: d + 8 = -7.
Third, subtract 8 from both sides. Your problem should look like: d = -7 - 8.
Fourth, simplify -7 - 8 to get -15. Your problem should look like: d = -15, which is your answer.

Hopefully this helps, I'm not exactly sure what you meant by "is equations," but this is how you solve the problem.

6 0

2 years ago

you go to a restaurant and spent 36.43 on food. if you give the waitress an 18% tip how much money would you get the waitress bi

kenny6666 [7]

Answer:

$43.03

Step-by-step explanation:

18% of $36.43 = $6.60 (6.5574)

$6.60 + $36.43 (price of food without tip)

$6.60 + $36.43 = $43.03

7 0

3 years ago