Step-by-step explanation:
let's aim for the slope intercept form of the line equation :
y = ax +b
a is the slope, b is the y intercept (the y value when x = 0).
the slope of a line is the ratio "y coordinate change / x coordinate change" when going from one point to another on the line.
I cannot draw here, but you know, what the slope triangle means : you draw a vertical line straight down from (2, 150) and a straight horizontal line left from (4, 130). where these lines cross, you have the third point of that triangle.
anyway, we don't need the drawn triangle to find the coordinate changes to calculate the slope.
between these 2 points
x changes by +2 (from 2 to 4)
y changes by -20 (from 150 to 130)
so, the slope is -20/+2 = -10
that brings the generic equation to
y = -10x + b
for b we simply use the coordinates of one of the points (I go for (2, 150)) and solve for b :
150 = -10×2 + b = -20 + b
b = 170
so, the full line equation is
y = -10x + 170
