Question

Can Someone Explain How To Do This Please. I Will Give A Medal. :D
(Solving System Equations)
2y = x + 1
–2x – y = 7

Answer 1

What have you tried?

Answer 2

I Havent Tried Anything Really Because I Never Understand How To Do These Problems.!

Answer 3

Try substitution. Only cuz it's my favorite and I like to avoid doing a bunch of algebra :)

Answer 4

Ok But What Do I Substitute.!? Im Really Confused :(

Answer 5

For instance:
\[ax + by = c\]
and
\[2dx + ey = f\]
rearrange to get one variable to use to substitute for the second equation!
i'll solve for y in the first one, to get:
\[y = \frac{ c }{ b } - \frac{ ax }{ b }\]
Now I can use that to substitue into the second equation (substitute y, because notice i have y = f(x)

Answer 6

substitute all of y ino the second equation!
\[2dx + e(\frac{ c }{ b }-\frac{ax}{b}) = f\]

Answer 7

Notice how you have only x's on this equation now! You can combine everything into one single equation, and use algebra to solve for x. once you get a numerical value for x, plug it back into equation 1 and solve for y.

Answer 8

So The I Would Put –2x – y = 7 Into The First Problem To Get y?

Answer 9

Well, you have to rearrange it so you have it in the form y = f(x)
You should ONLY have x's in your substitution equation.

Answer 10

\[y = \frac{x}{2} + \frac{1}{2}\]

Answer 11

Do I Have To Find An x Value Too? Or Whnever I Solve The Problem The x Will Be What Im Finding? So Confusing.!

Answer 12

Yes. Solve for both x and y. Of course.