I think of a number.

If I subtract 20 from my number, then square the result,

I get the same answer as

if I square my number, then subtract 20 from the result.

What is my number?

You must show an algebraic method (use letter x in your working).

I think of a number.

If I subtract 20 from my number, then square the result,

I get the same answer as

if I square my number, then subtract 20 from the result.

What is my number?

You must show an algebraic method (use letter x in your working).