How do you graph 2x+y=-22x+y=2 using intercepts?

2 Answers
May 29, 2017

Find two vaules for xx and yy that solve the equation, sketch them on a graph, and draw a line going through both points.

Explanation:

The easiest method is by finding two coordinates.
Find two vaules for xx and yy that solve the equation, sketch them on a graph, and draw a line going through both points.

To find a co-ordinate, we must pick any xx, or any yy.

Let's pick x=2x=2.

Then substitute into the equation:
2x+y=-22x+y=2
2(2)+y=-22(2)+y=2
4+y=-24+y=2
y=-2-4y=24
y=-6y=6

So the first coordinate is [2,-6][2,6]

Then repeat picking a different xx or yy value.
Assume y=7y=7
2x+y=72x+y=7
2x+7=72x+7=7
2x=02x=0
x=0x=0
Second coordinate: [0,7][0,7]

Then simply sketch a line between [2,-6][2,6] and [0,7][0,7]
graph{2x+y=-2 [-17.81, 17.81, -8.9, 8.91]}

May 29, 2017

"see explanation"see explanation

Explanation:

color(blue)"finding the intercepts"finding the intercepts

• " let x = 0, in the equation for y-intercept" let x = 0, in the equation for y-intercept

• " let y = 0, in the equation for x-intercept" let y = 0, in the equation for x-intercept

x=0to0+y=-2toy=-2larrcolor(red)" y-intercept"x=00+y=2y=2 y-intercept

y=0to2x+0=-2tox=-1larrcolor(red)" x-intercept"y=02x+0=2x=1 x-intercept

"plot these 2 points and draw a straight line through them"plot these 2 points and draw a straight line through them
graph{-2x-2 [-10, 10, -5, 5]}