Step-by-step explanation:
not everything is visible, and the points' coordinates have to optically estimated (particularly for the leftmost point).
I assume, we have the following points :
(-6, 1.5) (-3, 3)
(-3, 2) (1, 2)
(1, 1) (6, -9)
all 3 segments are lines with the basic function definition
y = ax + b
a is the slope of the line function and is always the factor of x.
it is the ratio y/x indicating how many units y changes, when x changes a certain amount of units when going from one point on the line to another.
b is the y-intercept (the y value when x = 0).
the first segment goes from (-6, 1.5) to (-3, 3).
x changes by +3 units (from -6 to -3).
y changes by +1.5 or 3/2 units (from 1.5 to 3).
the slope of the line is 3/2 / 3 = 3/(2×3) = 1/2
giving us the first part
y = (1/2)x + b
b we get by using the coordinates of one point (e.g. -3, 3) as x and y values and solve for b :
3 = (1/2)×-3 + b
3 = -3/2 + b
6/2 + 3/2 = b
9/2 = b
the full equation is
y = (1/2)x + 9/2 = (x + 9)/2
the second segment is a flat, horizontal line and is simply
y = 2
the third segment goes from (1, 1) to (6, -9) :
x changes by +5 units (from 1 to 6).
y changes by -10 units (from 1 to -9).
the slope of the line is -10/5 = -2
giving us the first part
y = -2x + b
b we get by using the coordinates of one point (e.g. 1, 1) as x and y values and solve for b :
1 = -2×1 + b
1 = -2 + b
3 = b
the full equation is
y = -2x + 3
