How do you graph $9x + 2y = -7$ by plotting points?

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Answer 1 · 2018-06-17T12:04:25

See a solution process below:

First, solve for two points which solve the equation and plot these points:

First Point: For $x = 1$

$(9 * 1) + 2y = -7$

$9 + 2y = -7$

$9 - color(red)(9) + 2y = -7 - color(red)(9)$

$0 + 2y = -16$

$2y = -16$

$(2y)/color(red)(2) = -16/color(red)(2)$

$y = -8$ or $(1, -8)$

Second Point: For $x = -1$

$(9 * -1) + 2y = -7$

$-9 + 2y = -7$

$-9 + color(red)(9) + 2y = -7 + color(red)(9)$

$0 + 2y = 2$

$2y = 2$

$(2y)/color(red)(2) = 2/color(red)(2)$

$y = 1$ or $(-1, 1)$

We can next plot the two points on the coordinate plane:

graph{((x-1)^2+(y+8)^2-0.1)((x+1)^2+(y-1)^2-0.1)=0 [-20, 20, -10, 10]}

Now, we can draw a straight line through the two points to graph the line:

graph{(9x+2y+7)((x-1)^2+(y+8)^2-0.1)((x+1)^2+(y-1)^2-0.1)=0 [-20, 20, -10, 10]}

How do you graph 9x + 2y = -79x + 2y = -7 by plotting points?