Question

What is the equation for the points (-2,3) (1,9) on a graph

Answer 1

9514 1404 393

Answer:

• y -9 = 2(x -1) . . . point-slope form
• y = 2x +7 . . . . slope-intercept form
• 2x -y = -7 . . . . standard form

Step-by-step explanation:

Perhaps you want the equation of the line that goes through these two points.

The slope of the line can be found using the formula ...

  m = (y2 -y1)/(x2 -x1)

  m = (9 -3)/(1 -(-2)) = 6/3 = 2

We can use one of the points to write the equation in point-slope form:

  y -k = m(x -h) . . . . . . . . line with slope m through point (h, k)

For slope 2 and point (1, 9) the equation is ...

  y -9 = 2(x -1) . . . . equation in point-slope form

__

We can eliminate parentheses and get y by itself to put the equation into slope-intercept form.

  y -9 = 2x -2

  y = 2x +7 . . . . . . equation in slope-intercept form

__

With a little further rearranging, we can put this into standard form. We can get that by adding -7-y to both sides of the equation.

  2x -y = -7 . . . . . equation in standard form