Answer:
a=2
Step-by-step explanation:
Please see attached picture for full solution.
Method 1: Substitute x with another number, other than the numbers that you have already tried. Zero is a good number to work with :)
Then, subst. the values of b and c which you have already found into the equation. Then simplify to arrive at your answer.
Method 2: Notice that when you expand the right hand side, only a(x)([tex] {x}^{2} [/tex]) can give you a [tex]x^{3} [/tex]term. Hence, compare the coefficients of [tex] {x}^{3} [/tex] on both sides. This method is quite safe since the value of a won't be affected in case the value of b and c is wrong.
