Polynomials Question (1 Viewer)

[Ambility]

How would you do this?

 

[leehuan]

P(x)=(x-1)(x+2)(ax+b)

If you sub for P(-1)=4 and P(2)=28 you're gonna get a simultaneous equation in a and b which allows you finish the question off.

 

[Ambility]

Shouldn't it be something like this though?

P(x) = c(x-1)(x+2)(ax+b)

Because we don't know the coefficient of the whole polynomial?

 

[leehuan]

Shouldn't it be something like this though?

P(x) = c(x-1)(x+2)(ax+b)

Because we don't know the coefficient of the whole polynomial?

Note that the a catered for it.

P(x)=(x-1)(x+2)(cax+bc)
P(x)=(x-1)(x+2)(dx+e)

You're thinking about:
P(x)=a(x-1)(x+2)(x+b)

 

[Ambility]

Note that the a catered for it.

P(x)=(x-1)(x+2)(cax+bc)
P(x)=(x-1)(x+2)(dx+e)

You're thinking about:
P(x)=a(x-1)(x+2)(x+b)

Thanks