equations of the line

Question

Find the equation of the line. write the equation using standard form notation. through (1,7) and (0,-2)

Answer 1

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The slope is:  m = (-2-7)/0-1) = -9/-1 = 9     [check: this is rise of 9 over run of 1]

 

The y-intercept (9,-2) is given, so you may write the line in slope-intercept form:    y = 9x - 2

 

In Standard Format (Ax+By=C), this is:   9x - y = 2

 

Check: 

     Does  9(1) - 7 = 2   ?

                  9-7 = 2   ?

                    2 = 2   ?yes

     Does  9(0) - (-2) = 2   ?

                         2 = 2   ?yes

Answer 2

slope M = (7 - -2)/(1 - 0) = 9/1 = 9

 

 

intercept B = y - m * x = 7 - 1 * 9 = 7 - 9 = -2

 

The equation is y = 9 x - 2