Question

What is the standard form equation of the line shown below? Graph of a line going through negative 2, 3 and 1, negative 3

Answer 1

Answer:

3. 2x + y = −1

Step-by-step explanation:

To find the equation of the line, we write it first in the slope-intercept form:

$y=mx+q$

where

m is the slope

q is the y-intercept

From the graph, we see that the line crosses the y-axis at y = -1, so the y-intercept is -1:

$q=-1$

Now we have to find the slope, by calculating the rate of change of the line through 2 points:

$m=\frac{y_2-y_1}{x_2-x_1}$

Taking the two points at (-2,3) and (1,-3), we find:

$m=\frac{-3-3}{1-(-2)}=\frac{-6}{3}=-2$

So the equation of the line is

$y=-2x-1$

Now we have to re-arrange it in the standard form, so in the form

$ax+bx=c$

where a, b and c are integer numbers.

To do that, we simply add +2x on both sides of the equation of the line in the slope-intercept form, and we get:

$y+2x=-1$

So, option 3).