How would you describe the us dollar if the forein exchange rate between the us dollar and british pound changed from 1: 1 to 1: 0.7?

The first ratio is

That is, 1 US Dollar equals 1 British Pound.

Then, the last ratio is

Which means that for one US Dollar you would get 70 cents of a British Pound.

As you can see, the second represents a devaluation of the US Dollar against the British Pounds. It has a lower value.

you can first factor out the n to get n(1+5). we know that 1+5 is 6, so we just have 6n.