Find the Slop and y intercept of a line

Question

Find the slope and y intercept (show all work)

 

2x+2y=20

Answer 1

2x + 2y = 20

 

Solve for y.

 

2x + 2y = 20

-2x           -2x

------------------

        2y = -2x + 20

 

Divide both sides by 2.

 

2y/2 = (-2x + 20) / 2

 

y = -2x/2 + 20/2

 

y = -x + 10   (this is now in y = mx + b format)

 

y intercept is (0, 10)

m (slope) = -1

Answer 2

Hi Again Theresa;

Great questions!  Keep these coming!

2x+2y=20

Let's simplify...

We can divide everything by 2...

(2x+2y)/2=(20)/2

x+y=10

Let's subtract x from both sides...

-x+x+y=10-x

y=10-x

 

The equation for a line is...

y=mx+b

m=slope

b=y intercept---the value of y when x=0

So let's reorganize the equation...

from...

y=10-x

to...

y=-x+10

The slope is -1, the y-intercept is 10.

Answer 3

Hey Theresa -- here's another angle ... since slope is "rise over run" (y/x), ignore the "20"

... 2x + 2y =0 ... 2y = -2x -> y/x = -2/2 ==> slope is -1

... y-intercept is when x=0 ... 2(0) + 2y = 20 --> y-int. occurs at (0,10) ... Regards :)