graph the equation 9x-9y=-81 using the x and y intercepts

Question

graph the equation 9x-9y=-81 using the x and y intercepts

Answer 1

 9x - 9y = 81

 

 

 X intercept:

 

  9X - 9( 0) = 81

 

 9X = 81   X = 9       X_intercept ( 9,0)

 

 Y intercept:

 

     9 ( 0 ) - 9Y = 81   

        Y = 81/ -9 = -9                              Y_{intercept  ( 0, -9)}

  

     To graph just locate the intercept points , connect and extend.

Answer 2

Hi Darsay;

The x-intercept is the value of x when y=0, (x,0).

The y-intercept is the value of y when x=0, (0,y).

9x-9y=-81

Let's make this easy.  Let's divide both sides by 9...

x-y=-9

You may want to divide both sides by NEGATIVE 9.  I do not recommend such.  The equation is currently in standard form...

Ax+By=C, neither A nor B equals zero, and A is greater than zero.

x-y=-9, is still in standard form in that A is greater than zero.  Multiplying this by a negative number would change that.

When y=0, x=-9, (-9,0).

When x=0, y=9, (0,9).

Plot both these points, and draw a line.

You can check your work by establishing the slope and verifying that your line is consistent with such.  The equation is in standard form...

x-y=-9

The slope is -A/B, -1/-1=1.

As your line rises one unit, it moves to the right one unit.

As your line descends one unit, it moves to the left one unit.