Is it asking to solve for a? 6 = a(x+2)(x-3)(x-2/5) ??
Yes! for when x = 0.
You have an equation y = f(x).
When it says, "y has an intercept of 6", then that means that y = 6 when x = 0, i.e. y = f(0) = 6.
So, 6 = a(0 + 2)(0 - 3)( 0 - 2/5)
6 = a*(12/5)
a = 5/2
Therefore y = (5/2)(x + 2)(x - 3)(x - 2/5)
This should be multiplied out to show a cubic polynomial and simplified.