# How do you solve #a^2=4a#?

##### 1 Answer

Feb 14, 2017

See below.

#### Explanation:

With quite some care!

Good practise is to re-write it as follows:

And then factor it:

So now you know that you have two solutions, ie

The temptation here, which exists all the way up the maths tree (to my branch, at least!), is to cancel out the

But that just throws away a solution :(

Zero is every bit as scarey as infinity, perhaps even scarier!