Question

3x^2-12x factorise in the form (x+b)(x-b)

Answer 1

`3x(x-4)`

Explanation:

`3x^2-12x` cannot be factorised in the form (x+b)(x-b) unless one of the b's is zero, so I wonder if the expression is incomplete?

To factorise
`3x^2-12x`, take out the common factor
`3x`:

`\implies3x(x-4)`

Therefore, x = 0 and x = 4

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`3x^2-12x` factorised in the form (x+b)(x-b) would be
`(3x+0)(x-4)`

but it is not usual to have a zero in a factorised form.