cubic polynomails

[monkeywantsabanana]

me again

so i have done this with the last question above (finding the equation) and subbed in all my values and have a set of simulataneous equations looking like this

when the point (0,8) is subbed in i am left with
d=8
sub in (2,0) the equation is- 0=8a+4b+2c+8
sub in (3,8) the equatio is 8=27a+9b+3c+8

my next question is what do i do next? how do i solve 3 simulataneous equations?

Is it a positive cubic or negative cubic?
Does it bounce off at coordinates (2,0) or does it cut the axis ?

I only see 2 equations and 3 unknowns - there must be another clue ?

[ben_ess12]

sorry i meant only 2
with 3 unknowns!

it is a positive cubic and it turns at the point (2,0) 

do i just solve as normal then?

[monkeywantsabanana]

I'm not too sure about the diagram - but here....
 
see attachment

[ben_ess12]

I'm not too sure about the diagram - but here....
 
see attachment

diagram was correct and thanks for that makes sense