Answer:
y - x = 6 and 18 + (-2x) = y
Step-by-step explanation:
The blue line has a slope of 1 and it passes the point y = 6 so according to the line formula y = mx + b the blue line is y = x + 6 which is y - x = 6 when rearranged.
The red line has a slope of -2 and passes through the point y = 18 so according to the line formula y = mx + b the blue line is y = -2x + 18 which is 18 + (-2x) = y when rearranged.
