Question 321434
(20,42) & (10,52)
Y=mX+b
m=slope=(Y2-Y1)/(x2-X1)=(52-42)/(10-20)=10/-10=-1 is the slope.
42=-1*20+b
42=-20+b
b=42+20
b=62
Y=-X+63 is the line equation.
{{{ graph( 300, 200, -6, 75, -10, 70, -x +63) }}} (graph 300x200 pixels, x from -6 to 75, y from -10 to 70, -x +63).