Function $f$ is a quadratic function. The graph of $y = f(x)$ in the …

Question

Prompt

Function

f

is a quadratic function. The graph of

y = f (x)

in the

x y

-plane has a vertex at

(9, - 7)

, contains the point

(8, - 9)

, and has a

y

-intercept at

(0, a)

. The graph of

y = 6 \cdot f (x)

has a

y

-intercept at

(0, b)

. What is the positive difference between

a

and

b