Answer:
the constant proportionality means the ratio between two directly proportional quantities.
so the constant proportionality will be 7.5÷6=1.25 or 10÷8=1.25 or 12.5÷10=1.25
constant proportionality should be same all through because it's a constant
-6 + 7 = 1 and -6*7 = -42
So f(x) = (x + 7)(x - 6)
frankly yes, because when you want inverse a function you must inverse it with line x=y
so when you inverse a function Df and Rf will convert together!
