mon29ika29
Answered

Get the answers you need at Westonci.ca, where our expert community is dedicated to providing you with accurate information. Explore thousands of questions and answers from a knowledgeable community of experts on our user-friendly platform. Our platform provides a seamless experience for finding reliable answers from a network of experienced professionals.

How is 3x-y=8 and x+2y=5 solved by combination (addition)?????


Sagot :

First, multiply the first equation by 2.

That turns the first equation into:

6x - 2y = 18

That way it can easily be added to the second equation:

6x - 2y = 16
x  + 2y = 5
---------------
7x = 21
==========

As you can see, the y disappeared, which was the objective of this operation.

Now the equations can be solved easily:

7x = 21
x = 3

Insert x=3 in the original equation:

3*3 - y = 8
9 - y = 8
9 = 8 + y
y = 1

So the result is:

x = 3
y = 1
Lilith
[tex]\begin{cases} 3x-y=8 \ \ / \cdot 2 \\ x+2y=5 \end{cases} \\\\ \begin{cases} 6x-2y=16 \\ x+2y=5 \end{cases} \\+--------\\7x=21 \ \ / :7\\\\x=3[/tex]

[tex]x+2y=5\\ \\ 3+2y=5 \\\\2y=5-3\\\\2y=2\ \ / :2\\\\y=1\\\\ \begin{cases} x=3 \\ y=1 \end{cases}[/tex]


We hope this information was helpful. Feel free to return anytime for more answers to your questions and concerns. We hope our answers were useful. Return anytime for more information and answers to any other questions you have. Thank you for trusting Westonci.ca. Don't forget to revisit us for more accurate and insightful answers.