20x+80y=0 is the standard form for a linear equation. Solve for y in order to convert the equation to slope-intercept form, y=mx+b, where m is the slope and b is the y-intercept.
20x+80y=0
Subtract 20x from both sides.
80y=−20x
Divide both sides by 80.
y=−20x80=
y=−14x
The slope, m is −14 and the y-intercept, b is 0.
Graphing the equation
y=−14x
Substitute 0 for x.
y=−14(0)=0
This gives us a point at the origin, 0,0.
To use the slope to determine other points, you can use the slope of −14. Starting at the origin, go up 1 and over −4, keeping going as far as you want. You can also start at the origin and go down 1 and over 4, keeping going as far as you want. You really only need two points to graph a straight line.
You can also substitute values for x into the equation and solve for y.
If x=4, y=−1
If x=−4, y=1
Below is how the graph of y=−14x would look.
graph{y=-1/4x [-10, 10, -5, 5]}
