All are equal except A/D = C/B
I replaced the values with numbers
a=5 b=10 c=50 d=100
10/5=100/50 so it’s not b/a = d/c
5/10=50/100 so it’s not a/b = c/d
5/50 = 10/100 so it’s not a/c = b/d
5/100 is NOT 50/10 so it’s NOT a/d = c/b
Therefore, slope of line DC = slope of line AC = -0.4.
The amount for the discount is 150$
