Algebra

We have this :

y  = −2(x + 6) (x + 2) (x  − 3) (x − 5)   + b

And when x = 0, y  = −360

So

−360  = (−2) (6)(2)( −3) ( −5)  + b

−360 = −360 + b    →   b = 0

So....the function is  

y  = −2(x + 6) (x + 2) (x  − 3) (x − 5)

y  =  -2 x^4 + 74 x^2 - 48 x - 360

Here's .the  graph :  https://www.desmos.com/calculator/svpexeicjl