Equations of Lines in slope-inercept form

It's a bit difficult to "solve" if we don't have a problem statement. Is one to put it in Slope-Intercept Form? If so, just solve for y.

x + y = 5

Subtract x

y = -x + 5

Slope = -1
Intercept = 5

Show us another one.
 
Thank you!!!!!

What about x-2y=4?

They don't give you an example on how to solve in the book. They give the answers in the back, but don't explain how to get there. At least I could see where I am going wrong!
 
hurlgyrl said:
Thank you!!!!!

What about x-2y=4?

They don't give you an example on how to solve in the book. They give the answers in the back, but don't explain how to get there. At least I could see where I am going wrong!
Click to expand...

As TK says, solve the equation for y. This will put the equation in this form:

\(\displaystyle y = mx +b\)

where m = the slope of the line and b = the y-intercept (where the line crosses the y-axis)

\(\displaystyle x-2y=4\Longrightarrow\)First, you must subtract \(\displaystyle x\) from both sides

\(\displaystyle -2y = -x+4\Longrightarrow\)Then, divide both sides by \(\displaystyle -2\).

\(\displaystyle \boxed{y=\frac{x}{2}-2}\Longrightarrowy \ \ or \ \ \boxed{y=\frac{1}{2}x-2}\Longrightarrow\)This is slope-intercept form.

The slope (m) is \(\displaystyle \frac{1}{2}\) and the y-intercept (b) is \(\displaystyle -2.\)
 
hurlgyrl said:
What about x-2y=4?
They don't give you an example on how to solve in the book. They give the answers in the back, but don't explain how to get there. At least I could see where I am going wrong
Click to expand...
I must disagree with your assessment, but I blame your misunderstanding on the book or your teacher. It is NOT your fault.

If you can solve the first one, you should be able to solve the second one. Unfortunately, many texts and teachers like to think there is a difference between the "One-Step" problem and the "Two-Step" problem. This, in my view, is horrible. Why not just teach the student the concept of reciprocal properties? Multiplication and divsion work together. Addition and subtraction work together. Once this idea is clear, no one possibly could care how many "steps" there are.

X + y = 5

The goal is to solve for 'y'.
We'll have to get rid of that 'x'.
'x' is attached to 'y' by addition. Unattach it by subtraction.

x - 2y = 4

The goal is to solve for 'y'.
We'll have to get rid of that 'x'.
'x' is attached to 'y' by addition. Unattach it by subtraction.

x - x - 2y = 4 - x

Simplify

-2y = 4 - x

Are we done?
The goal is to solve for 'y'.
We'll have to get rid of that '-2'.
'-2' is attached to 'y' by Multiplication. Unattach it by division.

-2y/(-2) = (4 - x)/(-2)

Simplify

y = (4 - x)/(-2)

You may wish to simplify further.
 
You must log in or register to reply here.
Top