Moises is determining the solution to the system of equations that is show below. equation representing line a: mc018-1.jpg points on line b: (3, –12) and (9, –24) step 1: determine the slope for b: mc018-2.jpg step 2: determine the y-intercept for b: mc018-3.jpg step 3: write the equation in slope-intercept form: mc018-4.jpg

equation of line is:
y = -2x - 6

Explanation:
The general form of the line is:
y = mx + c
where:
m is the slope of the line
c is the y-intercept

(a) getting the slope of the line:
slope of the line is calculated using the following rule:
slope of line (m) = (y2-y1) / (x2-x1) = (-24--12) / (9-3) = -2
The equation now becomes:
y = -2x + c

(b) getting the y-intercept:
The two given points belong to the line. Therefore, to get the y-intercept, we will use one of the points and substitute in the equation and solve for c.
I will use the point (3,-12)
y = mx + c
-12 = -2(3) + c
-12 = -6 + c
c = -12 + 6
c = -6

Based on the above, the equation of the line is:
y = -2x - 6

Hope this helps :)