# How do you solve #3x^2 + 9x = 12#?

##### 1 Answer

With practise these become easier to solve

#### Explanation:

Given:

Write as:

We are looking for

The only whole number factors of 12 are

This means we can only have one of:

'................................................................

The only whole number factors of 3 are

So the

'..............................................................

It is now a matter of trying them out and seeing what works.

I spot that from the factors of

we have:

So the factorisation must be

'~~~~~~~~~~~~~~~~~~~~~

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