contestada


Two points on a line are (-10, 1) and (5,-5). If
the y-coordinate of another point on the line is
-3, what is the x-coordinate?

Respuesta :

Answer:

The x-coordinate is 0

Step-by-step explanation:

step 1

Find the slope  m of the line

we have the points

(-10, 1) and (5,-5)

The formula to calculate the slope between two points is equal to

[tex]m=\frac{y2-y1}{x2-x1}[/tex]

substitute the values

[tex]m=\frac{-5-1}{5+10}[/tex]

[tex]m=\frac{-6}{15}[/tex]

Simplify

[tex]m=-\frac{2}{5}[/tex]

step 2

Find the equation of the line in slope intercept form

[tex]y=mx+b[/tex]

where

m is the slope

b is the y-intercept

we have

[tex]m=-\frac{2}{5}[/tex]

[tex]point\ (-10,1)[/tex]

substitute in the equation and solve for b

[tex]1=-\frac{2}{5}(-10)+b[/tex]

[tex]1=4+b[/tex]

[tex]b=1-4=-3[/tex]

The equation of the line is

[tex]y=-\frac{2}{5}x-3[/tex]

step 3

Find the x-coordinate of another point in the line if the y-coordinate is -3

For y=-3

substitute in the equation and solve for x

[tex]-3=-\frac{2}{5}x-3[/tex]

[tex]-3+3=-\frac{2}{5}x[/tex]

[tex]0=-\frac{2}{5}x[/tex]

[tex]x=0[/tex]

The point is (0,-3) -----> the y-intercept

therefore

The x-coordinate is 0