# What is the standard form of #y= (x+3)(1-3x)-7x#?

##### 1 Answer

#### Explanation:

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

To demonstrate what is happening:

Consider the product

We all know that the answer is 6.

We also know that

But what if we wrote 3 as

This is still so

The distributive property of multiplication simply means that we can write this as:

Can you see the way that multiplication by the 2 is 'spread around' (that is not a math term!!)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Doing the same thing with your question:

Given:

Consider just the brackets part:

Write as

This becomes:

Putting it all together:

Collecting like terms gives:

It just takes a little practice that is all!