How do you graph x+2y=10 by plotting points?

1 Answer
Mar 24, 2016

See explanantion

Explanation:

Given" "x+2y=10

changing the formula so that it is in standard form

Subtract x from both sides giving

" "2y=10-x

Divide both sides by 2 so that we have y on its own.

" "y=5-x/2
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This graph can be drawn if only two points are known but it is better to do 3 as a check to see if there is an error in your calculation. No error would mean that all the points line up. If not then check you calculations.

color(blue)("First point")

I chose the point where the graph crosses the x-axis
( x intercept ). To do this set y=0

" "0=5-x/2 From this we observe that x=10

color(blue)("Point 1 "-> (x,y)->(10,0))

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
color(blue)("Second point")

I chose the point where the graph crosses the y-axis (y intercept).
To do this we set x=0

" "y=5-0/2 From this we observe that y=5

color(blue)("Point 2 "-> (x,y)->(0,5))

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
color(blue)("Third point")

"I choose "color(blue)(x=2)

Substitute this in our equation and we have

color(brown)(y=5-x/2 -> )color(green)( y= 5-(color(blue)(2))/2

color(blue)(y=+4 )

color(blue)("Point 2 "-> (x,y)->(2,4))
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(magenta)("Do not forget the extend the line to the edges of the graph.

Tony B