66.1k views
1 vote
What is the equation for the points (-2,3) (1,9) on a graph

User Adonna
by
7.5k points

1 Answer

6 votes

9514 1404 393

Answer:

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

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

What is the equation for the points (-2,3) (1,9) on a graph-example-1
User Tim Bellis
by
7.5k points