# Math Help - Surds

1. ## Surds

An easy question that I can't seem to do.

Show that (2√2+2)² = 12+8√2

The method I have been taught is the grid method (diagram below is meant to be a grid I can't seem to draw it so use your imagination :P ):

......2√2.......2
2√2..X.......4√2
.
2.....4√2......4

But I can't do 2√2 x 2√2. Some help? I can work its meant to be 8 so I can do the question but how would I do that?

2. Hello,

Originally Posted by Ifailatmaths
An easy question that I can't seem to do.

Show that (2√2+2)² = 12+8√2

The method I have been taught is the grid method (diagram below is meant to be a grid I can't seem to draw it so use your imagination :P ):

......2√2.......2
2√2..X.......4√2
.
2.....4√2......4

But I can't do 2√2 x 2√2. Some help? I can work its meant to be 8 so I can do the question but how would I do that?
2√2 x 2√2=(2x√2)x(2x√2)=(2x2)x(√2x√2)=4x(√2)²=4x2

3. Originally Posted by Moo
Hello,

2√2 x 2√2=(2x√2)x(2x√2)=(2x2)x(√2x√2)=4x(√2)²=4x2