The question asks to find a cubic equation given point A (0/18) slope here is 0. Point B only given the x=20 and slope is -0.6.
Please help, been trying to solve it for so long now. 
1.) y=ax^3+bx^2+cx+d
2.) y’=3ax^2+2bx+c
-0,6=1200a+40b+1c
18=0a+0b+0c+1d
